Real-Time Monitoring of Cellular Cultures with Electrolyte-Gated Carbon Nanotube Transistors.

Cell-based biosensors constitute a fundamental tool in biotechnology, and their relevance has greatly increased in recent years as a result of a surging demand for reduced animal testing and for high-throughput and cost-effective in vitro screening platforms dedicated to environmental and biomedical diagnostics, drug development, and toxicology. In this context, electrochemical/electronic cell-based biosensors represent a promising class of devices that enable long-term and real-time monitoring of cell physiology in a noninvasive and label-free fashion, with a remarkable potential for process automation and parallelization. Common limitations of this class of devices at large include the need for substrate surface modification strategies to ensure cell adhesion and immobilization, limited compatibility with complementary optical cell-probing techniques, and the need for frequency-dependent measurements, which rely on elaborated equivalent electrical circuit models for data analysis and interpretation.

High-Aspect-Ratio Semiconducting Polymer Pillars for 3D Cell Cultures.

Hybrid interfaces between living cells and nano/microstructured scaffolds have huge application potential in biotechnology, spanning from regenerative medicine and stem cell therapies to localized drug delivery and from biosensing and tissue engineering to neural computing. However, 3D architectures based on semiconducting polymers, endowed with responsivity to visible light, have never been considered. Here, we apply for the first time a push-coating technique to realize high aspect ratio polymeric pillars, based on polythiophene, showing optimal biocompatibility and allowing for the realization of soft, 3D cell cultures of both primary neurons and cell line models.

Photocatalytic Activity of Polymer Nanoparticles Modulates Intracellular Calcium Dynamics and Reactive Oxygen Species in HEK-293 Cells.

Optical modulation of living cells activity by light-absorbing exogenous materials is gaining increasing interest, due to the possibility both to achieve high spatial and temporal resolution with a minimally invasive and reversible technique and to avoid the need of viral transfection with light-sensitive proteins. In this context, conjugated polymers represent ideal candidates for photo-transduction, due to their excellent optoelectronic and biocompatibility properties. In this work, we demonstrate that organic polymer nanoparticles, based on poly(3-hexylthiophene) conjugated polymer, establish a functional interaction with an cell model (Human Embryonic Kidney cells, HEK-293).

The Photophysics of Polythiophene Nanoparticles for Biological Applications.

In this work the photophysics of poly(3-hexylthiophene) nanoparticles (NPs) is investigated in the context of their biological applications. The NPs, made as colloidal suspensions in aqueous buffers, present a distinct absorption band in the low-energy region. On the basis of systematic analysis of absorption and transient absorption (TA) spectra taken under different pH conditions, this band is associated with charge-transfer states generated by the polarization of loosely bound polymer chains and originating from complexes formed with electron-withdrawing species.

Tattoo-Paper Transfer as a Versatile Platform for All-Printed Organic Edible Electronics.

The use of natural or bioinspired materials to develop edible electronic devices is a potentially disruptive technology that can boost point-of-care testing. The technology exploits devices that can be safely ingested, along with pills or even food, and operated from within the gastrointestinal tract. Ingestible electronics can potentially target a significant number of biomedical applications, both as therapeutic and diagnostic tool, and this technology may also impact the food industry, by providing ingestible or food-compatible electronic tags that can "smart" track goods and monitor their quality along the distribution chain.

Semiconducting polymers are light nanotransducers in eyeless animals.

Current implant technology uses electrical signals at the electrode-neural interface. This rather invasive approach presents important issues in terms of performance, tolerability, and overall safety of the implants. Inducing light sensitivity in living organisms is an alternative method that provides groundbreaking opportunities in neuroscience.

Poly(3-hexylthiophene) nanoparticles for biophotonics: study of the mutual interaction with living cells.

We report on the mutual interaction between poly(3-hexylthiophene) nanoparticles (P3HT-NPs) and human embryonic kidney (HEK-293) cells. P3HT-NPs, prepared in sterile conditions and efficiently uptaken within the live cells cytosol, show well-ordered morphology, high colloidal stability and excellent biocompatibility. Electrophysiology and calcium imaging experiments demonstrate that physiological functions of live cells are fully preserved in the presence of P3HT-NPs.

Conjugated polymers for the optical control of the electrical activity of living cells.

The possibility to optically excite the electrical activity of living cells by using exogenous absorbers is gaining more and more interest in the neuroscience and biotechnology community. Conjugated polymers, inherently sensitive to visible light, were recently proposed as candidates to this goal. To date, however, only one polymer type, namely regio-regular poly-3-hexylthiophene, has been tested as the active material.

Optical Control of Living Cells Electrical Activity by Conjugated Polymers.

Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications. In particular, conjugated polymers display several optimal properties as substrates for biological systems, such as good biocompatibility, excellent mechanical properties, cheap and easy processing technology, and possibility of deposition on light, thin and flexible substrates. These materials have been employed for cellular interfaces like neural probes, transistors for excitation and recording of neural activity, biosensors and actuators for drug release.

Photothermal cellular stimulation in functional bio-polymer interfaces.

Hybrid interfaces between organic semiconductors and living tissues represent a new tool for in-vitro and in-vivo applications, bearing a huge potential, from basic researches to clinical applications. In particular, light sensitive conjugated polymers can be exploited as a new approach for optical modulation of cellular activity. In this work we focus on light-induced changes in the membrane potential of Human Embryonic Kidney (HEK-293) cells grown on top of a poly(3-hexylthiophene) (P3HT) thin film.

Mesenchymal stem cell differentiation on electrochemically modified titanium: an optimized approach for biomedical applications.

Purpose: To speed up the osteointegration process, surface-treated titanium has been widely used in dental and orthopedic applications. The present work describes a new silicon-based anodic spark deposition (ASD) treatment and investigates the properties of the surfaces obtained, focusing on their capability to modulate the osteogenic differentiation potential of adult mesenchymal stem cells (MSCs).

Methods: The surfaces examined were obtained from commercially pure grade 2 titanium by a single-step ASD (SUM) eventually followed by a thermal treatment in alkali solution (SUMNa), while acid-etched titanium (AE; NextMaterials s.

A simple method to generate adipose stem cell-derived neurons for screening purposes.

Strategies involved in mesenchymal stem cell (MSC) differentiation toward neuronal cells for screening purposes are characterized by quality and quantity issues. Differentiated cells are often scarce with respect to starting undifferentiated population, and the differentiation process is usually quite long, with high risk of contamination and low yield efficiency. Here, we describe a novel simple method to induce direct differentiation of MSCs into neuronal cells, without neurosphere formation.