Nanoperforations in poly(lactic acid) free-standing nanomembranes to promote interactions with cell filopodia

Abstract

Nanoperforated poly(lactic acid) (PLA) free-standing nanomembranes (FsNMs) have been prepared using a two-step process: (1) spin-coating a mixture of immiscible polymers to provoke phase segregation and formation of appropriated nanofeatures (i.e. phase separation domains with dimensions similar to the entire film thickness); and (2) selective solvent etching to transform such nanofeatures into nanoperforations. For this purpose, PLA has been mixed with polyethylene glycol (PEG) and poly(vinyl alcohol) (PVA). Unfortunately, the characteristic of PLA:PEG mixtures were not appropriated to prepare nanoperforated FsNMs. In contrast, perforated PLA FsNMs with pores crossing the entire film thickness, which have been characterized by scanning electron microscopy and atomic force microscopy, were obtained using PLA:PVA mixtures. The diameter () of such pores has been controlled through both the PLA:PVA ratio and the processing conditions of the mixtures, FsNMs with pores of  0.8 m, 170 nm and 65 nm being achieved. Investigations on nanoperforated FsNMs (i.e. those with   170 and 65 nm), which are the more regular, reveal that pores crossing the entire membrane thickness do not affect the surface wettability of PLA but drastically enhances the cellular response of this biomaterial. Thus, cell proliferation assays indicate that cell viability in PLA with perforations of  170 nm is 2.6 and 2.2 higher than in nonperforated PLA and PLA with perforations of  65 nm, respectively. This excellent response has been attributed to the similarity between the nanoperforations with  170 nm and the filopodia filaments in cells (100-200 nm), which play a crucial role in cell migration processes. The favorable interaction between the perforated membrane nanofeatures and cell filopodia has been corroborated by optical and scanning electron microscopies.3

Confinement of a β-barrel protein in nanoperforated free-standing nanomembranes for ion transport

“…PLA:PVA mixture is prepared under vigorous stirring. 29 In order to reduce the diameter properties of non-perforated PLA FSNMs prepared using a procedure similar to that employed in this work (i.e. spin-coating) were carefully examined by Takeoka and coworkers 47 using a bulging test.…”

“…Nanoperforated PLA nanomembrames. Nanoperforated PLA FSNMs were prepared using an already described two-step procedure: 29 The incorporation of Omp2a preserving its -barrel structure as proved by CD ( Figure S3), induces drastic changes in the physical properties of nanoperforated PLA NMs (Figure 3a). Indeed, the wettability significantly increases upon the incorporation of the protein.…”

“…As a result, although supported OM protein- In this work, nanoperforated PLA FSNMs were fabricated using an approach based on the combination of spin-coating with phase segregation using immiscible PLA:PVA mixtures, and the subsequent removal of PVA domains via selective solvent etching. 29 The quantitative evaluation of this procedure using different conditions has shown that the diameter of the nanopores decreases from 17073 nm to 6532 nm if a 90:10…”

Poly-γ-glutamic Acid Hydrogels as Electrolyte for Poly(3,4-ethylenedioxythiophene)-Based Supercapacitors

“…In contrast, the morphology of the rest of the hydrogels resembles that of microperforated polymeric films ( Figure S4). 39 Accordingly, LPGGA-2, LPGGA-4 and HPPGA-6 hydrogels were chosen as suitable SE for OESC devices due to their mechanical stability and open structure.…”

Micro‐Phase Separation within Epoxy Resin Yields Ultrathin Mesoporous Membranes with Increased Scalability by Conversion from Spin‐ to Dip‐Coating Process

“…Since PCGF is devoid of nitrogen, this strongly suggests that PEI accumulates at the bottom side during casting and corroborates the presence of a compositional gradient as a consequence of the proposed phase separation mechanism. Regardless of the underlying mechanism, these janus‐type membrane properties with the distinctly different undulating bottom surface might be of considerable interest for applications in adherent cell culture, cellular‐ and tissue barrier and coculture models given the thickness of under 100 nm.…”