PNIPAAm/PCL Electrospun Mats for Aligned Cell Sheet Detachment

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Solution Overview

Problem

Current methods for generating aligned cell sheets are resource-intensive and limited in thickness, which restricts their functional application in tissue graft therapy, and existing techniques for cell alignment are challenging to implement effectively.

Innovation Solution

Electrospinning of a fiber mat comprising a blend of poly(N-isopropylacrylamide) (PNIPAAm) and poly(caprolactone) (PCL) with specific ratios, allowing for the formation of aligned fibers that support cell growth and detachment, eliminating the need for chemical synthesis and high-resolution patterning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If micropatterning or photolithography is used to generate surface anisotropy for cell alignment, then high resolution and precise cell alignment are achieved, but resource intensity and manufacturing complexity increase significantly

Engineering Contradiction:

Improvecell alignment precisionVSAvoidmanufacturing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the physical parameters of the electrospinning process, specifically applying a rotating collector at controlled speeds to transform the random fiber deposition into aligned fiber structures. This parameter change enables cell alignment without requiring complex micropatterning equipment or photolithography processes, thus resolving the contradiction between alignment precision and manufacturing complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the complex mechanical and chemical systems of micropatterning and photolithography with a simpler electrospinning system that uses electrical fields and mechanical rotation. This substitution achieves comparable cell alignment precision while dramatically reducing device complexity and resource requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Shape

If electrospun fiber scaffolds are used for tissue transplantation, then cell alignment and tissue structure are improved, but the scaffold thickness is limited to 1-2 cell layers which restricts functional application

Engineering Contradiction:

Improvetissue structureVSAvoidscaffold thickness

Core Design Contradiction:

ShapeVSLength of moving object

Solution Approach 1:

The invention segments the scaffold into multiple stacked layers of electrospun fibers, each layer contributing to the overall thickness while maintaining aligned structure. This segmentation approach enables the construction of thicker scaffolds (beyond 1-2 cell layers) that preserve tissue architecture and support functional applications, resolving the contradiction between structure quality and thickness

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If PNIPAAm is used as a surface coating for cell sheet detachment, then cell sheet release is enabled through temperature control, but chemical synthesis and photolithography patterning are required which increase complexity

Engineering Contradiction:

Improvecell sheet detachmentVSAvoidprocess complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The invention makes the electrospun fiber mat itself multi-functional by incorporating both the structural support function and the temperature-responsive detachment function into a single material system. The fibers are engineered to exhibit PNIPAAm-like thermoresponsive behavior directly, eliminating the need for separate surface coating steps, chemical synthesis, and photolithography patterning, thus resolving the contradiction between ease of operation and process complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The PNIPAAm/PCL fiber mats enable the generation of intact, anisotropic cell sheets that can mimic tissue architecture, supporting cell viability and alignment, and facilitating controlled detachment, thereby overcoming the limitations of existing methods in terms of resource intensity and thickness.

Implementation Method 1

Electrospinning, on the other hand, is a relatively simple and inexpensive technique to fabricate polymer nano- and micro-fibers

Methodology Applied

Scientific EffectElectrospinning: Electrohydrodynamics

Implementation Method 2

PNIPAAm undergoes a rapid coil-to-globule transition at its lower critical solution temperature (LCST) of 32° C. that determines how the hydrophilic and hydrophobic domains interact with water

Methodology Applied

Scientific EffectLower critical solution temperature (LCST) transition: Phase Change

Implementation Method 3

for cells grown on PNIPAAm-grafted tissue culture plates, cell sheet detachment is possible when the incubation temperature is lowered below the LCST: PNIPAAm expands, forcing the cell sheet to detach

Methodology Applied

Scientific EffectThermosensitive expansion: Thermal Expansion

Data Source

PatentUS20240360604A1Electrospun PNIPAAm/PCL Fiber Mats for Aligned Cell Sheets

Publication Date: 2024.10.31 BOARD OF RGT THE UNIV OF TEXAS SYST

AI summary

The present invention provides compositions comprising aligned fibers of electrospun PNIPAAm and poly (ε-caprolactone) (PCL) (denoted PNIPAAm/PCL fibers). The PNIPAAm/PCL compositions enable enhanced growth and detachment of intact anisotropic cell sheets. The compositions do not require chemical modification or resource-intensive techniques, thus saving time and expense, and have the potential to generate tissue-specific, aligned cell sheets for transplant studies.