A self-assembly based supramolecular bioink with hierarchical control As a new bioprinting tool

Tissue engineering aims to capture details of the extracellular matrix (ECM) that stimulate cell growth and tissue regeneration. Molecularly complex materials or advanced additive fabrication techniques are often used to capture aspects of the ECM. Promising biofabrication techniques often lack nano and molecular scale control, as well as materials that can recreate the natural ECM or selectively guide cell behaviour. On the other hand, complex biomaterials based on molecular self-assembly tend to lack reproducibility and order beyond the nanoscale. We propose a new material fabrication platform that integrates the benefits of bioprinting and molecular self-assembly to overcome the current major limitations. Our approach relies on the co-assembly of peptide amphiphiles (PAs) with biomolecules and/or proteins found in the ECM, whilst exploiting the droplet-on-demand (DoD) printing process. Taking advantage of the interfacial fluid forces during printing, it is possible to guide the self-assembly into aligned or disordered nanofibers, hydrogel structures of different geometries and sizes, surface topographies and higher-ordered structures made from multiple hydrogels. The co-assembly process can be performed during printing and in cell-friendly conditions, whilst exhibiting high cell viability (\u3e 88 %). Moreover, multiple cell types can be spatially distributed on the outside or embedded within the tuneable biomimetic scaffolds. The combination of self-assembly with 3D-bioprinting, provides a basis for a new biofabrication platform to create hydrogels of complex geometry, structural hierarchy and tuneable chemical composition. Please click Additional Files below to see the full abstract

Peptide-protein coassembling matrices as a biomimetic 3D model of ovarian cancer

Bioengineered three-dimensional (3D) matrices expand our experimental repertoire to study tumor growth and progression in a biologically relevant, yet controlled, manner. Here, we used peptide amphiphiles (PAs) to coassemble with and organize extracellular matrix (ECM) proteins producing tunable 3D models of the tumor microenvironment. The matrix was designed to mimic physical and biomolecular features of tumors present in patients. We included specific epitopes, PA nanofibers, and ECM macromolecules for the 3D culture of human ovarian cancer, endothelial, and mesenchymal stem cells. The multicellular constructs supported the formation of tumor spheroids with extensive F-actin networks surrounding the spheroids, enabling cell-cell communication, and comparative cell-matrix interactions and encapsulation response to those observed in Matrigel. We conducted a proof-of-concept study with clinically used chemotherapeutics to validate the functionality of the multicellular constructs. Our study demonstrates that peptide-protein coassembling matrices serve as a defined model of the multicellular tumor microenvironment of primary ovarian tumors

The multi-facets of sustainable nanotechnology : lessons from a nanosafety symposium

An international symposium for nanosafety was held recently at the Nanyang Technological University in Singapore. Topics relating to understanding nanomaterial properties, tools, and infrastructure required for predicting hazardous outcomes, measuring nanomaterial exposure levels, systems approach for risk assessment and public's perception of nanotechnology were covered. The need for a multidisciplinary approach, across both natural and social sciences, for developing sustainable nanotechnology solutions was heavily emphasized. This commentary highlights the major issues discussed and the commitment of the nanosafety research community in Singapore to contribute collectively to realise the vision of sustainable nanotechnology

Integrated Transcriptomics, Metabolomics, and Lipidomics Profiling in Rat Lung, Blood, and Serum for Assessment of Laser Printer-Emitted Nanoparticle Inhalation Exposure-Induced Disease Risks

settings Open AccessArticle Integrated Transcriptomics, Metabolomics, and Lipidomics Profiling in Rat Lung, Blood, and Serum for Assessment of Laser Printer-Emitted Nanoparticle Inhalation Exposure-Induced Disease Risks by Nancy Lan Guo 1,*,Tuang Yeow Poh 2,Sandra Pirela 3,Mariana T. Farcas 4,Sanjay H. Chotirmall 2,Wai Kin Tham 5,Sunil S. Adav 5,Qing Ye 1,Yongyue Wei 6,Sipeng Shen 2,David C. Christiani 2,Kee Woei Ng 3,7,8,Treye Thomas 9,Yong Qian 4 andPhilip Demokritou 3 1 West Virginia University Cancer Institute/School of Public Health, West Virginia University, Morgantown, WV 26506, USA 2 Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore 3 Center for Nanotechnology and Nanotoxicology, Department of Environmental Health, T. H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA 4 Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA 5 Singapore Phenome Centre, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore 6 Key Lab for Modern Toxicology, Department of Epidemiology and Biostatistics and Ministry of Education (MOE), School of Public Health, Nanjing Medical University, Nanjing 210029, China 7 School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore 8 Environmental Chemistry and Materials Centre, Nanyang Environment & Water Research Institute, Singapore 637141, Singapore 9 Office of Hazard Identification and Reduction, U.S. Consumer Product Safety Commission, Rockville, MD 20814, USA * Author to whom correspondence should be addressed. Int. J. Mol. Sci. 2019, 20(24), 6348; https://doi.org/10.3390/ijms20246348 Received: 2 December 2019 / Revised: 12 December 2019 / Accepted: 13 December 2019 / Published: 16 December 2019 (This article belongs to the Special Issue Advances in Nanostructured Materials between Pharmaceutics and Biomedicine) Download PDF Browse Figures Review Reports Cite This Paper Abstract Laser printer-emitted nanoparticles (PEPs) generated from toners during printing represent one of the most common types of life cycle released particulate matter from nano-enabled products. Toxicological assessment of PEPs is therefore important for occupational and consumer health protection. Our group recently reported exposure to PEPs induces adverse cardiovascular responses including hypertension and arrythmia via monitoring left ventricular pressure and electrocardiogram in rats. This study employed genome-wide mRNA and miRNA profiling in rat lung and blood integrated with metabolomics and lipidomics profiling in rat serum to identify biomarkers for assessing PEPs-induced disease risks. Whole-body inhalation of PEPs perturbed transcriptional activities associated with cardiovascular dysfunction, metabolic syndrome, and neural disorders at every observed time point in both rat lung and blood during the 21 days of exposure. Furthermore, the systematic analysis revealed PEPs-induced transcriptomic changes linking to other disease risks in rats, including diabetes, congenital defects, auto-recessive disorders, physical deformation, and carcinogenesis. The results were also confirmed with global metabolomics profiling in rat serum. Among the validated metabolites and lipids, linoleic acid, arachidonic acid, docosahexanoic acid, and histidine showed significant variation in PEPs-exposed rat serum. Overall, the identified PEPs-induced dysregulated genes, molecular pathways and functions, and miRNA-mediated transcriptional activities provide important insights into the disease mechanisms. The discovered important mRNAs, miRNAs, lipids and metabolites may serve as candidate biomarkers for future occupational and medical surveillance studies. To the best of our knowledge, this is the first study systematically integrating in vivo, transcriptomics, metabolomics, and lipidomics to assess PEPs inhalation exposure-induced disease risks using a rat model

Visible light crosslinkable human hair keratin hydrogels

Abstract Keratins extracted from human hair have emerged as a promising biomaterial for various biomedical applications, partly due to their wide availability, low cost, minimal immune response, and the potential to engineer autologous tissue constructs. However, the fabrication of keratin‐based scaffolds typically relies on limited crosslinking mechanisms, such as via physical interactions or disulfide bond formation, which are time‐consuming and result in relatively poor mechanical strength and stability. Here, we report the preparation of photocrosslinkable keratin‐polyethylene glycol (PEG) hydrogels via the thiol‐norbornene “click” reaction, which can be formed within one minute upon irradiation of visible light. The resulting keratin‐PEG hydrogels showed highly tunable mechanical properties of up to 45 kPa in compressive modulus, and long‐term stability in buffer solutions and cell culture media. These keratin‐based hydrogels were tested as cell culture substrates in both two‐dimensional surface seeding and three‐dimensional cell encapsulation, demonstrating excellent cytocompatibility to support the attachment, spreading, and proliferation of fibroblast cells. Moreover, the photocrosslinking mechanism makes keratin‐based hydrogel suitable for various microfabrication techniques, such as micropatterning and wet spinning, to fabricate cell‐laden tissue constructs with different architectures. We believe that the unique features of this photocrosslinkable human hair keratin hydrogel promise new opportunities for their future biomedical applications

Tissue engineering a skin equivalent using a novel combination of poly(lactic-co-glycolic acid) mesh with cell sheets

Ph.DDOCTOR OF PHILOSOPH

Reduced contraction of skin equivalent engineered using cell sheets cultured in 3D matrices

10.1016/j.biomaterials.2006.04.020Biomaterials27264591-4598BIMA

Probing the relevance of 3D cancer models in nanomedicine research

For decades, 2D cell culture format on plastic has been the main workhorse in cancer research. Though many important understandings of cancer cell biology were derived using this platform, it is not a fair representation of the in vivo scenario. In this review, both established and new 3D cell culture systems are discussed with specific references to anti-cancer drug and nanomedicine applications. 3D culture systems exploit more realistic spatial, biochemical and cellular heterogeneity parameters to bridge the experimental gap between in vivo and in vitro settings when studying the performance and efficacy of novel nanomedicine strategies to manage cancer. However, the complexities associated with 3D culture systems also necessitate greater technical expertise in handling and characterizing in order to arrive at meaningful experimental conclusions. Finally, we have also provided future perspectives where cutting edge 3D culture technologies may be combined with under-explored technologies to build better in vitro cancer platforms.Accepted versio

Recent omics advances in hair aging biology and hair biomarkers analysis

Aging is a complex natural process that leads to a decline in physiological functions, which is visible in signs such as hair graying, thinning, and loss. Although hair graying is characterized by a loss of pigment in the hair shaft, the underlying mechanism of age associated hair graying is not fully understood. Hair graying and loss can have a significant impact on an individual's self-esteem and self-confidence, potentially leading to mental health problems such as depression and anxiety. Omics technologies, which have applications beyond clinical medicine, have led to the discovery of candidate hair biomarkers and may provide insight into the complex biology of hair aging and identify targets for effective therapies. This review provides an up-to-date overview of recent omics discoveries, including age-associated alterations of proteins and metabolites in the hair shaft and follicle, and highlights the significance of hair aging and graying biomarker discoveries. The decline in hair follicle stem cell activity with aging decreased the regeneration capacity of hair follicles. Cellular senescence, oxidative damage and altered extracellular matrix of hair follicle constituents characterized hair follicle and hair shaft aging and graying. The review attempts to correlate the impact of endogenous and exogenous factors on hair aging. We close by discussing the main challenges and limitations of the field, defining major open questions and offering an outook for future research.Ministry of Education (MOE)Submitted/Accepted versionThis research was supported by the Ministry of Education AcRF-Tier 1 grants RT10/20 & RG7/22