1,721,063 research outputs found
Functionalization protocols of silicon micro/nano-mechanical biosensors
No full textFunctionalization is a key element in biodetection technologies such as micro/nano-mechanical sensors. Since assay sensitivity and stability drastically depends on a proper bioreceptor immobilization, the sensing surface must be first chemically modified with uniform, well-packed, and robust layers. Here, we describe three functionalization protocols that we developed for the surface modification with amino, aldehyde, and carboxyl groups of micro/nano-mechanical biosensor
Functional 3D printing: Approaches and bioapplications
Full text link3D printing technology has become a mature manufacturing technique, widely used for its advantages over the traditional methods, such as the end-user customization and rapid prototyping, useful in different application fields, including the biomedical one. Indeed, it represents a helpful tool for the realization of biodevices (i.e. biosensors, microfluidic bioreactors, drug delivery systems and Lab-On-Chip). In this perspective, the development of 3D printable materials with intrinsic functionalities, through the so-called 4D printing, introduces novel opportunities for the fabrication of “smart” or stimuli-responsive devices. Indeed, functional 3D printable materials can modify their surfaces, structures, properties or even shape in response to specific stimuli (such as pressure, temperature or light radiation), adding to the printed object new interesting properties exploited after the fabrication process. In this context, by combining 3D printing technology with an accurate materials’ design, functional 3D objects with built-in (bio)chemical functionalities, having biorecognition, biocatalytic and drug delivery capabilities are here reported
Biomedical Applications
No full textIn recent years, 3D printing technology has become a sufficiently mature technique to allow not only the production of objects starting from a design modeling but also a possible customization through the introduction of functionality by the end user. This rapid prototyping technique represents a very promising technology for device fabrication with different application fields (e.g., biological, environmental, food, aerospace), offering advantages over traditional manufacturing methods.
Moreover, the 3D printing archetype has introduced novel opportunities for the realization of smart devices, where the added value lies in their intrinsic functionality. In fact, 3D-printed functional materials can transform their structure in response to specific stimuli (e.g., temperature, pH, light radiation, etc.), adding to the printed object interesting properties to take advantage of. Recently, this paradigm has been explored and expanded by researcher’s/engineer’s community with the aim of realizing 3D printable objects that present exploitable chemical functionalities.
In this chapter, functional 3D objects for bio-applications have been reported, combining 3D printing technology with an accurate material engineering. The result is a single step 3D-printed object with intrinsic chemical functionalities that could be exploited to produce immunoassay-based and/or enzymatically active devices for biosensing purposes and precision medicine
Ultra-Thin Plasma-Polymerized Functional Coatings for Biosensing: Polyacrylic Acid, Polystyrene and Their Co-Polymer
Full text linkRecently, many efforts have been done to chemically functionalize sensors surface to achieve selectivity towards diagnostics targets, such as DNA, RNA fragments and protein tumoural biomarkers, through the surface immobilization of the related specific receptor. Especially, some kind of sensors such as microcantilevers (gravimetric sensors) and one-dimensional photonics crystals (optical sensors) able to couple Bloch surface waves are very sensitive. Thus, any kind of surface modifications devoted to functionalize them has to be finely controlled in terms of mass and optical characteristics, such as refractive index, to minimize the perturbation, on the transduced signal, that can affect the response sensitivity towards the detected target species. In this work, the study and optimization of ultra-thin plasma polymers and copolymers, compatible with these constrains and obtained from the vapours of acrylic acid containing a carboxylic (−COOH) group and styrene (an aromatic molecule with a vinyl as substituent at the ring), are reported. The obtained plasma polyacrylic acid (PPAA), plasma polystyrene (PPST) and their copolymer (PPAA-ST), characterized through optical contact angle analysis (OCA), Fourier transform infrared (FTIR) spectroscopy in attenuated total reflection (ATRFTIR), X-ray photoelectrons spectroscopy (XPS), and atomic force microscopy (AFM), are shown to match specific and critical requirements, such as low thickness (∼40 nm) and refractive index (∼1.5), high surface density of reactive groups (1015-1016 COOH/cm2), bioantifouling properties where required, reproducibility, and chemical resistance and stability
Protein immobilization on nanoporous silicon functionalized by RF activated plasma polymerization of Acrylic Acid
No full textPlasma Enhanced Chemical Vapor Deposition (PECVD) technique is used to polymerize Acrylic Acid for the surface functionalization of porous silicon samples with different pore dimensions. The polymer shows free -COOH groups also at the pores inner surface, suitable for the immobilization of fluorescent labeled Protein A. The stability of the polymer, its role in the protection from aging of the porous matrix and the efficiency of the functionalization for the binding of protein A have been characterized by ATR - FTIR, SEM, Optical Contact Angle and Fluorescence Microscopy. The polymerization process is well controllable and suitable for the functionalization of porous silicon leaving free carboxylic groups at the surface ready for the immobilization of biochemical species for sensing application
Innovative Detection of Biomarkers Based on Chemiluminescent Nanoparticles and a Lensless Optical Sensor
Full text linkThe identification and quantification of biomarkers with innovative technologies is an urgent need for the precise diagnosis and follow up of human diseases. Body fluids offer a variety of informative biomarkers, which are traditionally measured with time-consuming and expensive methods. In this context, lateral flow tests (LFTs) represent a rapid and low-cost technology with a sensitivity that is potentially improvable by chemiluminescence biosensing. Here, an LFT based on gold nanoparticles functionalized with antibodies labeled with the enzyme horseradish peroxidase is combined with a lensless biosensor. This biosensor comprises four Silicon Photomultipliers (SiPM) coupled in close proximity to the LFT strip. Microfluidics for liquid handling complete the system. The development and the setup of the biosensor is carefully described and characterized. C-reactive protein was selected as a proof-of-concept biomarker to define the limit of detection, which resulted in about 0.8 pM when gold nanoparticles were used. The rapid readout (less than 5 min) and the absence of sample preparation make this biosensor promising for the direct and fast detection of human biomarkers
Laser-induced anisotropic wettability on azopolymeric micro-structures
Full text linkThe light-induced deformation of a micro-textured photo-sensitive polymeric material is exploited for modifying the surface hydrophobicity along deterministic directions. Arrays of azopolymeric micro-pillars are fabricated over large area and irradiated with a green laser. Upon laser irradiation, the micro-pillars deform reversibly along a direction parallel to the laser polarization, resulting in elongated shapes with controllable eccentricity. Such a locally anisotropic topography induces a directional yet reversible change of hydrophobicity, as measured by contact angles varying within a range of 30 degrees. Published by AIP Publishing
Neuromorphic Light‐Responsive Organic Matter for in Materia Reservoir Computing
Full text linkMaterials able to sense and respond to external stimuli by adapting their internal state to process and store information, represent promising candidates for implementing neuromorphic functionalities and brain-inspired computing paradigms. In this context, neuromorphic systems based on light-responsive materials enable the use of light as information carrier, allowing to emulate basic functions of the human retina. In this work it is demonstrated that optically-induced molecular dynamics in azopolymers can be exploited for neuromorphic-type of data processing in the analog domain and for computing at the matter level (i.e., in materia). Besides showing that azopolymers can be exploited for data storage, it is demonstrated that the adaptiveness of these materials enables the implementation of synaptic functionalities including short-term memory, long-term memory, and visual memory. Results show that azopolymers allow event detection and motion perception, enabling physical implementation of information processing schemes requiring real-time analysis of spatio-temporal inputs. Furthermore, it is shown that light-induced dynamics can be exploited for the in materia implementation of the unconventional computing paradigm denoted as reservoir computing. This work underscores the potential of azopolymers as promising materials for developing adaptive, intelligent photo-responsive systems that mimic some of the complex processing abilities of biological systems
Optical and structural properties of amorphous silicon-nitrides and silicon-oxycarbides: Application of multilayer structures for the coupling of Bloch Surface Waves
No full textHydrogenated amorphous silicon-nitrides (a-SiNx:H) and -oxycarbides (a-SiOxCy:H) were grown by plasma enhanced chemical vapor deposition (PECVD) at low power density (40 - 60 mW/cm2) using silane, ammonia, methane and carbon dioxide as silicon, nitrogen, carbon and oxygen precursors respectively. Their refractive index dispersion curves were analyzed by means of specular reflectance spectroscopy and their structural properties by FTIR spectroscopy. Taking advantage from their properties such as tunable refractive index, the alloys were fruitfully applied in dielectric stratified structures, optimized for surface electromagnetic waves propagation
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