345 results about "Cell migration" patented technology

The present invention relates to the field of biomedicine and discloses a platelet-rich plasma for anti-aging and promoting tissue repair and regeneration, a preparation method, and an application thereof, comprising the following steps: obtaining concentrated platelet plasma, and treating the concentrated platelet plasma with low-intensity pulsed ultrasound; the treatment conditions are one of the following treatment methods: 1) the treatment power is 2 to 5 W / cm 2 , the pulse period is 50%, and the ultrasonic treatment time is 2~10 min; 2) First, the first ultrasonic treatment is performed: using 0.2~1.0 W / cm 2 , the pulse period is 50%, ultrasonic treatment is 1~5 min; then the second ultrasonic treatment is carried out: 1.5~5.0 W / cm 2 , the pulse period is 50%, and the ultrasonic treatment is 1 to 5 minutes; the present invention adopts a special ultrasonic treatment system to obtain a PRR product with special activation and lysis characteristics. The product has active substances that are beneficial to tissue repair and regeneration and anti-aging, and shows excellent effects in promoting cell proliferation, cell migration and wound healing.

The present invention relates to the field of biomedical materials, particularly to a novel composite collagen material for wound repair, and more specifically to a method for preparing a novel composite collagen material comprising recombinant humanized collagen type 21 (ColpepA1 21) and its use in wound repair. The present invention utilizes ColpepA1 21 to significantly promote key biological reactions in the wound healing process, including accelerating cell migration, enhancing skin hydration and barrier function, and improving the stability and elasticity of skin structure. The resulting novel composite collagen material effectively promotes wound healing and cell regeneration, alleviating oxidative damage.

The invention provides recombinant IV type collagen and application thereof, and relates to the technical field of protein engineering. In the invention, an amino acid residue repetitive unit with good biological activity and stability in the human-derived IV-type collagen is found, and the amino acid residue repetitive unit is used as a core for repeating and constructing the recombinant IV-type collagen, so that the novel human-derived recombinant IV-type collagen with biological activity is obtained. The human-derived recombinant IV-type collagen provided by the invention is a small-molecular-weight protein, is easy to absorb by a human body, is good in safety, can remarkably promote secretion of collagen, also has the effects of promoting cell adhesion and cell migration, and has a good application prospect in the aspects of basement membrane repair and remodeling. A new functional component is provided for products for repairing and tightening the skin, resisting aging, resisting wrinkles, preserving moisture and the like.

The invention provides a recombinant XVII type collagen fragment, and the protein fragment sequence of the recombinant XVII type collagen fragment is shown as SEQ ID No.1. The recombinant XVII type collagen fragment is screened and designed based on a natural collagen sequence, has a triple helix structure, has good biological activity, can effectively exert functions, and has a good promotion effect on cell migration, cell proliferation and cell adhesion. The method for preparing the recombinant XVII type collagen fragment has the advantages that the process steps are simplified, the expression efficiency of the recombinant protein is improved, and the production cost is reduced. The recombinant XVII type collagen fragment provided by the invention has good mechanical properties and biological activity, and can be used for preparing therapeutic drugs and biological materials.

The invention discloses an electroactive dressing used for promoting bone cell differentiation and bone regeneration and used for negative pressure therapy and a manufacturing method. The manufacturing method of the electroactive dressing comprises the steps that S1, a PLLA / BG spinning solution is prepared; s2, preparing a PLLA / BG nanofiber membrane through electrostatic spinning; s3, vacuum drying; s4, PAMAM-NH2 surface modification, the negative pressure treatment dressing relates to the technical field of negative pressure treatment dressings, when mechanical deformation is generated during negative pressure work, the piezoelectric biological film generates continuous electric stimulation, and the electric stimulation has positive and beneficial effects on osteoblasts and bone tissue physiological processes. The generated electric effect continuously collects functional electrolyte in surrounding tissues, and the functional electrolyte is separated in the wound by the dendrimer PAMAM-NH2, so that excessive exudation caused by negative pressure treatment is effectively made up. Meanwhile, the flow of the electrolyte further strengthens a local electric signal, so that cell migration and osteoblast proliferation and differentiation are effectively promoted.

The invention belongs to the field of biological medicine and material science, and particularly relates to an intelligent response type piezoelectric nanofiber dressing and a preparation method and application thereof. According to the preparation method, polyvinylidene fluoride-trifluoroethylene, a high polymer material and inorganic nanoparticles are blended and spun through an electrostatic spinning technology, and then a photo-thermal component coating is subjected to surface in-situ oxidation and self-polymerization, so that the composite fiber membrane is prepared. Under the stimulation of ultrasound (US) and near-infrared laser (Laser), the fiber membrane can cooperatively activate the piezoelectric effect and the photothermal effect, generate a dynamic electric field and local high temperature, realize multi-mode cooperative killing of bacteria (the antibacterial rate exceeds 99%), and simulate an endogenous electric field to promote cell migration and wound healing. The dressing has good mechanical properties (the Young modulus is 15-20 MPa), hydrophilicity (the contact angle is about 30 degrees), biocompatibility and stability, is suitable for treatment of chronic infected wounds such as diabetes mellitus and the like, and has the advantages of on-demand activation and intelligent response.

The invention relates to a phytoextraction external liniment for promoting black hair growth and a preparation method thereof. According to the liniment, a polygonum multiflorum extract, a cacumen biotae supercritical extract and molecular embedded black sesamin in a specific proportion are taken as cores and are matched with an azone-menthol transdermal enhancer and a propylene glycol-olive oil carrier, and black hair growth is synergistically promoted through triple mechanisms of activating tyrosinase, inhibiting melanocyte apoptosis and promoting cell migration. The preparation method adopts a gradient temperature extraction combined molecular embedding technology, the polygonum multiflorum is subjected to stepped purification at 40-60 DEG C-80 DEG C to retain thermosensitive active ingredients, the black sesamin is embedded by beta-cyclodextrin to improve the stability, and finally, the nano microemulsion is formed through two-stage homogeneous emulsification. The liniment can efficiently permeate into the deep layer of hair follicles, the efficiency of turning white hair into black is remarkably improved, and skin irritation is avoided.

The invention relates to a micro-fluidic chip integrated with a pneumatic micro valve, a preparation method and a use method. The micro-fluidic chip comprises an interface gas layer, a thin film layer and a fluid layer, the film layer is arranged between the interface gas layer and the fluid layer; the thin film layer is provided with a plurality of concentration gradient control channels, each concentration gradient control channel comprises a dilution inlet, a pneumatic micro-valve array, an observation area and an outlet which are connected in sequence, liquid enters the concentration gradient control channels through the dilution inlets, enters the flow channels provided with the pneumatic micro-valve arrays through the fishbone-shaped mixing micro-channels, and enters the flow channels through the fishbone-shaped mixing micro-channels; pneumatic micro valves in the pneumatic micro valve array are controlled through the interface gas layer so as to realize dynamic regulation and control of concentration gradients, and the fluid layer is used for accommodating dilution liquids with different concentration gradients; the observation area is used for observing diluted liquid in the fluid layer. The technical problem of real-time reconstruction of the concentration gradient of the micro-fluidic chip in the experiment process is solved, and the dynamic experiment requirements of scenes such as cell migration observation and drug time-varying response are met.

The invention discloses a gel microneedle loaded with silver nanoparticles and a preparation method and application thereof.The extract nano-silver (AB-AgNPs) is prepared through a green synthesis strategy, a drug-loaded microneedle system is constructed based on carboxymethyl chitosan-vanillic aldehyde-polyvinyl alcohol (CMCS-Va-PVA) composite gel, the AB-AgNPs prepared through the technology are uniform in particle size and stable in dispersion, and the drug-loaded microneedle has the advantages that the drug-loaded microneedle is good in drug-loaded performance and good in drug-loaded performance; the crystal has a typical face-centered cubic crystal structure and metal state Ag0 characteristics; the gel microneedle has good mechanical strength and forming effect, the AB-AgNPs and the gel matrix are stably combined through hydrogen bonds, the chemical properties are kept unchanged, and the system has broad-spectrum efficient bacteriostatic activity and biocompatibility; an in-vitro experiment proves that the green synthesized gel microneedle loaded with the silver nanoparticles has a remarkable capability of promoting the healing of L929 cell tissues; a rat wound experiment proves that the gel microneedle can regulate and control an inflammatory factor network and promote cell migration and tissue regeneration, healing of common and infected wounds is remarkably accelerated, and the wound residue ratio in 9 days is as low as 2.7% and 10.9% respectively.

The invention relates to the technical field of medical instruments, in particular to a photo-piezoelectric hydrogel dressing for wound repair. The hydrogel dressing realizes self-energized micro-electrical stimulation and anti-oxidation-antibacterial-anti-inflammatory integrated treatment through'energy-drug 'double closed-loop synergy: the PVDF / ZnO nanofiber on the upper layer can convert human body micro-motion and external light into micro-electrical stimulation to promote cell migration, proliferation and angiogenesis; the curcumin at the lower layer cooperates with the nano-silver to block the'oxidative stress-inflammation-infection 'vicious circle of chronic wounds. The dressing is soft and fit, does not need an external power supply, is excellent in biocompatibility, provides a self-driven multifunctional nursing scheme for refractory wounds, and has wide clinical popularization and market application prospects.

A skin care composition includes a plurality of agents that include at least one retinol derivative that may comprise, for example, hydroxypinacolone retinoate, and at least one bark extract that may comprise, for example, Eperua falcata bark extract, the plurality of agents providing reduced retinol associated inflammation as compared with a composition that includes the at least one retinol and lacks the at least one bark extract. The plurality of agents may also include hydroxy acid, for example, comprising lactic acid. The composition may confer one or a combination of increased skin cell proliferation, improved cellular migration, improved cellular differentiation, an anti-inflammatory retinol genetic signature as demonstrated by via bulk-RNA sequencing of human keratinocytes and restores epidermal disruption and reduce IL-1A and IL-23 inflammatory cytokines in human ex-vivo skin models of chronic inflammation.

The invention discloses a traditional Chinese medicine composition for treating recurrent urinary tract infection as well as a preparation method and application thereof. The traditional Chinese medicine composition is prepared from 30-90 parts of astragalus membranaceus, 3-9 parts of cordyceps mycelia, 12-36 parts of rhizoma anemarrhenae, 10-30 parts of golden cypress and 6-18 parts of cinnamon. According to the pathogenesis characteristics of recurrent urinary tract infection and the principle of treatment based on syndrome differentiation of traditional Chinese medicine, the optimal raw material composition and dosage part ratio are obtained through screening, simplification and optimization of a large number of experiments, and the traditional Chinese medicine composition can remarkably improve the frequent micturition symptom, bacterial load and bladder pathological injury of rUTI mice. In addition, the drug-containing serum can promote migration of the SV-HUC-1 cells and reduce the level of inflammatory factors secreted by co-culture of the SV-HUC-1 cells and the UTI89 cells; the adhesion and internalization of the UTI89 to the cells are reduced. In addition, according to different bacterial strains and mouse modeling results, it is found that the modeling rate is obviously increased in a mode of enhancing infection every 24 hours, a recurrent urinary tract infection model of UTI89 infected C57BL / 6J is constructed, and a stable model is provided for screening drugs for treating recurrent urinary tract infection.

The utility model discloses a culture device for a cell migration experiment, which relates to the field of cell experiment equipment and comprises a culture dish and a cell culture plate with various hole site specifications such as 24 holes, 12 holes, 6 holes and the like, the culture device structurally comprises a bottom plate and a hole plate at the top of the bottom plate, and a plurality of culture hole sites are distributed at the top of the hole plate in a rectangular array manner. The culture hole site is used for adherent cell culture, the bottom of the culture hole site is provided with at least one membrane strip, the top of the membrane strip is provided with grid scale marks, and the bottom of the culture hole site and the bottom of the membrane strip are also provided with grid scale marks. The scratching step of a cell migration experiment can be simplified in the process of a cell culture experiment, the scratching device is convenient to use and can be used at any time when being taken, and the cell migration scratching experiment can be carried out for multiple times in one experiment.

The invention relates to the technical field of medical instruments, in particular to a variable-diameter blood seepage prevention artificial blood vessel based on a multi-layer composite structure, which comprises a composite artificial blood vessel main body, and a bioactive composite layer is arranged on the outer side of a gradient pore polyester woven layer. The main body of the composite artificial blood vessel is composed of more units such as the first artificial blood vessel part, the second artificial blood vessel part, the third artificial blood vessel part and the fourth artificial blood vessel part, and the inner diameter difference between every two adjacent units is 2.0 mm, so that the variable-diameter structure is more suitable for natural blood vessels of people clinically; in addition, the bioactive composite layer comprises type I collagen, heparin sodium and VEGF sustained release microspheres, the collagen / heparin composite layer forms a hydrated gel barrier when in contact with blood, the errhysis volume is reduced to 1 / 16 of that of a traditional product, endothelial cell migration is promoted by utilizing TiOnanotube array layer and VEGF sustained release synergy, and in addition, under the pulsating pressure of 120 mmHg, through 1 million times of cycle tests, the effective rate of the collagen / heparin composite layer is greatly increased. The structural integrity retention rate is larger than 99%, and the mechanical fatigue resistance is high.

This invention discloses recombinant type III collagen, its preparation method, and its applications. The amino acid sequence of the recombinant type III collagen is shown in SEQ ID NO: 9. The recombinant type III collagen integrates the RGDV highly active motif and the EKEK hydrophilic stable domain with the core structure of type III collagen to achieve an integrated design of "high activity and long-lasting effect". The in vitro cell migration and collagen secretion effects are improved by more than 50% compared with wild type. Through anti-enzyme cleavage site modification and hydrophilic modification, the in vivo residence half-life is significantly prolonged to meet the long-term repair needs of the dermis.

The application discloses an active oxygen response type bacteriostatic and repair promoting hydrogel and a preparation method and application thereof, the hydrogel is formed by disulfide bond cross-linked hydrogel in response to active oxygen free radicals in the vagina of vaginitis patients through thiol modified hyaluronic acid (HASH), and can enhance in-vivo retention by thiol and vaginal tissue interaction. Cationic surfactant such as didecyldimethylammonium chloride (DDAC) as the bacteriostatic component of the hydrogel, efficiently killing pathogenic bacteria while having good biocompatibility, and is not prone to cause bacterial drug resistance. As a natural immune regulator, beta-glucan regulates the vaginal microenvironment, promotes the polarization of macrophages into anti-inflammatory M2 type and promotes cell migration, etc., to promote the repair of the vaginal immune barrier, regulate the vaginal flora, and reduce the probability of vaginitis recurrence. The HASH hydrogel provides an efficient, convenient and highly transformative potential strategy to provide more choices for the treatment of vaginitis.

This invention discloses an exovesicle from *Ashitsubaki* (Tomorrow's Leaf), its preparation method, and its application in the preparation of skin wound repair products, belonging to the field of plant exovesicle technology. The method uses fresh *Ashitsubaki* leaf stems and leaves as raw materials. After crushing, the material is filtered through a filter bag. The filtrate is then enzymatically hydrolyzed, centrifuged, and finally filtered through a tangential flow filtration system and further filtered to remove impurities and bacteria, yielding uniformly sized *Ashitsubaki* exovesicles. The preparation method of this invention is simple, and the obtained *Ashitsubaki* exovesicles exhibit excellent cell migration and skin healing promotion abilities, showing broad application prospects in the preparation of skin wound repair products.

The present invention relates to novel cell culture and transfection methods using a wildtype Caf1 ("Caf1-WT") polymer or a variant thereof. Use of a Caf1-WT polymer or a variant thereof to increase cell viability, cell proliferation, cell migration and / or cell clustering; promote the formation of a 3D cell structure; and / or promote suspension cell culture of cells that are normally adherent are also provided herein.

The invention discloses recombinant collagen III + X as well as a preparation method and application thereof, and belongs to the technical field of biochemical engineering. The amino acid sequence of the recombinant collagen III + X provided by the invention is shown as SEQ ID NO: 1, and the recombinant collagen III + X is formed by repeating human III type collagen 387-467 amino acid fragments twice and connecting human X type collagen 521-680 amino acid fragments to the C end. Experiments prove that the recombinant III + X collagen and proline hydroxylase are co-expressed to form a stable triple helix structure, and the recombinant III + X collagen has great advantages in the aspects of cell migration, safety and the like, and can be used as a raw material for preparing wound dressings and skin care products.

Proposed are antibodies specifically binding to PTK7 and a use thereof and, more particularly, PTK7 neutralizing antibodies specifically binding to PTK7 to inhibit PTK function, and a use thereof for inhibiting angiogenesis, cell growth, cell migration, and cell invasion. The human PTK7 neutralizing monoclonal antibodies have been found to independently exhibit an effective inhibitory effect on cancer cell growth, migration, invasion in esophageal squamous cell carcinoma and triple-negative breast cancer, and angiogenesis. Therefore, the human PTK7 neutralizing monoclonal antibodies can be applied to various PTK7-positive carcinomas and angiogenic diseases, and can be further developed as a targeted drug therapy for intractable cancers and angiogenic diseases to be used as a core global treatment drug for the same.

The invention discloses a hederacoside C deglycosylation derivative and a preparation method and application thereof.The hederacoside C deglycosylation derivative is prepared from hederacoside C through specific glycosidase hydrolysis, different products can be flexibly regulated and enriched on the basis of selectivity of different glycosidase to glucosidic bonds and glycosyl sites, the preparation method is simple, reaction conditions are mild, and the hederacoside C deglycosylation derivative is suitable for industrial production. The method is suitable for large-scale mass production. The hederacoside C deglycosyl derivative does not show obvious cytotoxicity to human immortalized keratinocytes, has the effect of promoting cell proliferation and the activity of promoting cell migration, and can obviously inhibit LPS (lipopolysaccharide)-induced cell apoptosis. Besides, the partial hederacoside C deglycosyl derivatives can reduce inflammatory factor level rise caused by wounds, remarkably promote wound healing and reduce formation of wound scars, and have good application prospects in preparation of drugs or skin care products for promoting wound repair.

This invention relates to a vulnerary multifunctional composition, based on unripe coffee cherries (peel, mucilage, beans and silverskin), seed extract of Trigonella foenum-graecum, with one or more tissue-inducing molecules derived from the secondary metabolites of both plants. The unexpected and surprising ability of this new composition to solve the problems of chronic non-healing wounds addresses a long felt unmet need in the medical arts. Through a multifaceted approach, it combats microbial infections, reduces chronic inflammation, counters oxidative stress, enhances immune responses, promotes angiogenesis, regulates protease activity, stimulates collagen deposition, increases growth factor availability, facilitates cell migration, and prevents persistent infections. These novel integrated therapies represent a breakthrough in addressing macroscopic wound healing while targeting the underlying microscale mechanisms. This invention also relates to methods for preparing, using, and administering the multifunctional composition for timely healing in mammals with various skin lesions.

The application discloses a kind of preparation and application of multi-target small nucleic acid drug based on small activation RNA technology, and is related to the field of biotechnology.The preparation method of the multi-target small nucleic acid drug includes the following steps: (1) selecting at least two anti-disease genes according to target disease;(2) intercepting the sequence of 1000 base pairs of the promoter region upstream of the coding region of the anti-disease gene;(3) according to the promoter sequence, avoid CpG island and locate the segment of species conservation, and cut a sequence containing 19 base length as a sense strand;(4) design an antisense strand according to the sense strand, and the 19 base of the antisense strand and the sense strand are completely complementary;(5) add two deoxythymine or uracil to the 3' end of each chain.The multi-target small nucleic acid drug has good therapeutic effect on heart failure, and has strong cancer cell killing ability and inhibition ability of cancer cell migration, and has wide application prospect.

The invention provides a PDRN-containing dual-network hydrogel dressing applying marine biomass resources, a preparation method and an application of the PDRN-containing dual-network hydrogel dressing. The preparation method of the dressing comprises the following steps: S1, preparing a chitosan solution; s2, preparing a PDRN solution; s3, slowly dropwise adding the PDRN solution into the chitosan solution, and stirring to form a PDRN-chitosan mixed solution; s4, an AgNPs-GSH solution is prepared and obtained; s5, slowly pouring the AgNPs-GSH solution into the PDRN-chitosan mixed solution, adding the gelatin aqueous solution, gently stirring, adding the KCl solution, quickly stirring, and standing to form a hydrogel dressing; the double-network hydrogel dressing containing PDRN has the double effects of resisting inflammation, resisting bacteria and promoting healing, and carrageenan and chitosan promote cell migration and regeneration; chitosan / PDRN compositely protects nucleic acid, enzymolysis is avoided, GSH buffers Ag < + > release, the chitosan / PDRN and carrageenan are co-distributed in a matrix to provide a long-acting sterilization barrier, the PDRN anti-inflammatory repair effect is complementary with the carrageenan, and the whole system achieves continuous release and biological activity maintenance.

The present disclosure relates to CXCR3 ligands having CXCR3-expressing-cell migration-inducing activity, and specifically to amino acid modifications and amino acid sequences that are important for CXCR3-expressing-cell migration-inducing activity.

The invention belongs to the technical field of exosomes, and particularly relates to an engineered exosome for overexpressing EGF and FGF as well as a preparation method, a product and application of the engineered exosome. An LAMP2B fusion expression technology is adopted, EGF and FGF are directionally anchored to the surface of a 293T cell source exosome membrane, free factor degradation is avoided, and the problem that the carrying amount of natural exosome factors is insufficient is solved. Through the synergistic effect of two factors, the exosome can reverse proliferation inhibition of DHT on hair follicle hair papilla cells, improve the cell migration ability, promote AGA mouse hair follicles to recover from a resting period to a growing period and block hair follicle microminiaturization, and finally reconstruct an AGA hair follicle microenvironment to achieve functional hair growth. Cell experiments confirm that the compound can repair hair follicle cells damaged by DHT, animal experiments show that the AGA mouse hair coverage rate is increased, the safety is good, the primary clinical effect is achieved, an efficient, safe and flexible new scheme is provided for AGA treatment, and the compound has good clinical transformation potential.

The utility model relates to a fine line device for an experiment for detecting cell migration ability, which comprises a fine line main body, the adhesive sheets are arranged at the two ends of the fine line main body, and adhesive protective layers are arranged on the adhesive sheets; and the two ends of the fine line main body exceed the adhesive sheet. The thin line main body with the structure can be conveniently adhered to a culture plate through the adhesive sheet and is also convenient to tear off, and a blank area is left after the thin line main body is torn off and is used for observing and recording the cell migration capability. The utility model provides a fine line device for an experiment for detecting cell migration ability, which is detachable, simple and convenient to operate, and capable of ensuring the consistency of scratch width and reducing damage to scratch edge cells and the bottom surface of a culture plate. The problems that scratches engraved by a gun head are inconsistent in width, and damage to cells and the bottom face of a culture plate is large are solved.

An object of the present invention is to provide a method for obtaining cells having a high migration ability or cells having a high proliferation ability as cells having an increased therapeutic effect on diseases. The present invention is a method for preparing cells for treating diseases, a method for promoting a migration ability of cells, and a method for promoting a proliferative ability of cells, each of the methods comprising subjecting cells to ultrasonic treatment. The frequency of the ultrasonic treatment is preferably 30 kilohertz to 2.0 megahertz, and the cells are preferably mesenchymal stem cells. In addition, the present invention also includes cells obtained by the preparation method of the present invention.

The invention provides a nucleic acid molecule, a mesenchymal stromal cell for promoting angiogenesis and application thereof, and relates to the technical field of biomedicine, the nucleic acid molecule encodes an HGF protein, or encodes a VEGF165 protein and an HGF protein; the first signal peptide is used as a signal peptide of VEGF165 protein, and the second signal peptide is used as a signal peptide of HGF protein. Through a gene modification strategy, the MSC cell containing the nucleic acid molecule stably and efficiently expresses VEGF165 and / or HGF, and the expression quantity of the VEGF165 and / or HGF is obviously higher than that of the MSC without the nucleic acid molecule. The capability of promoting endothelial cell migration is realized; meanwhile, the cells can also remarkably promote proliferation and tube formation of HUVEC cells, and the strong angiogenesis promoting effect of the cells is further proved. The technical problem that in the prior art, nucleic acid molecules for expressing VEGF165 or / HGF cannot be stably and efficiently expressed is solved.

This invention discloses recombinant humanized type III collagen, its preparation method, and its applications, belonging to the field of medical materials technology. The amino acid sequence of this recombinant humanized type III collagen is any one of SEQ ID No. 2-6. Compared to traditional extraction methods, the amino acid sequence of this recombinant protein is highly consistent with that of natural human proteins, completely avoiding the biosafety risks of pathogens, prions, etc., that may exist during animal-derived extraction, while also exhibiting lower immunogenicity. Furthermore, this protein effectively maintains the natural biological activity and stability of collagen. When used as a wound dressing, this material can efficiently promote cell migration, spreading, and proliferation, accelerate tissue regeneration and wound healing, while possessing excellent biocompatibility, controllable degradation, and low immunogenicity.