Evidence map›Paper›PMID 42621959›Full record

ArticleACS applied polymer materials2026

Engineering Multilayer Poly(ethylene glycol) Hydrogels via Off-Stoichiometry Thiol-Ene Chemistry.

Ridhi Pradhan, Ravinun Khamleart, Waqas Saleem, Michael J McShane

Abstract read
In one paragraph

Article in ACS applied polymer materials, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Ridhi PradhanDepartment of Biomedical Engineering, Texas A & M University, College Station, Texas 77843, United States.ORCID https://orcid.org/0009-0000-6316-8087
Ravinun KhamleartDepartment of Biomedical Engineering, Mahidol University, Nakhon Pathom 73170, Thailand.
Waqas SaleemDepartment of Biomedical Engineering, Texas A & M University, College Station, Texas 77843, United States.
Michael J McShaneDepartment of Biomedical Engineering, Texas A & M University, College Station, Texas 77843, United States.ORCID https://orcid.org/0000-0001-6838-3982

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Multilayer hydrogels with spatially controllable mechanical and functional properties are increasingly valuable, yet their utility is often constrained by fabrication challenges such as weak interfacial adhesion as well as reliance on cytotoxic photoinitiators and UV exposure. This study presents a simple, robust, and photoinitiator-free method to engineer multilayer poly-(ethylene glycol) (PEG) hydrogels using off-stoichiometry thiol-ene (OSTE) Michael addition chemistry. By deliberately utilizing an alternating thiol-rich and vinyl sulfone-rich PEG formulation, residual functional groups are preserved at the layer interfaces and subsequently form covalent bonds between the adjacent layers, enabling strong interfacial adhesion without UV irradiation, photoinitiators, or adhesives. The resulting hydrogels exhibited rapid and tunable gelation (1-5 min), with mechanical properties spanning ∼0.5-6 kPa through varying polymer concentration (5-10 wt %) and thiol-ene ratio (0.6-1.6). Ellman's assay confirmed the presence of stoichiometry-dependent unreacted thiol groups, validating the proposed interfacial bonding mechanism. Peel tests revealed strong interfacial adhesion, with failure occurring within the bulk material rather than at the interface. Nanoindentation further revealed spatially defined stiffness profiles across the multilayer construct, confirming precise mechanical compartmentalization. The hydrogels displayed tunable swelling behavior and degradation profiles depending on the formulations. Additionally, all single- and multilayer hydrogels maintained high cytocompatibility (>90% NIH/3T3 mice fibroblast viability) independent of polymer concentration, thiol-ene ratios, or layering. Incorporation of alginate microparticles provided an additional strategy for modulating hydrogel properties, significantly reducing swelling and enhancing stiffness while preserving structural integrity. Overall, the findings established a platform for engineering heterogeneous hydrogel constructs with spatially controlled properties, biofunctionality, and compatibility features that make them relevant for biomedical applications.

Indexed as

biomaterialscompartmentalizationinterfacial adhesionMichael additionmultilayer hydrogeloff-stoichiometry thiol–enespatially controlled mechanics

Identifiers

PMID42621959
PMCPMC13488143

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.