The role of elasticity on adhesion and clustering of neurons on soft surfaces

The question of whether material stiffness enhances cell adhesion and clustering is still open to debate. Results from the literature are seemingly contradictory, with some reports illustrating that adhesion increases with surface stiffness and others suggesting that the performance of a system of cells is curbed by high values of elasticity. To address the role of elasticity as a regulator in neuronal cell adhesion and clustering, we investigated the topological characteristics of networks of neurons on polydimethylsiloxane (PDMS) surfaces - with values of elasticity (E) varying in the 0.55-2.65 MPa range. Results illustrate that, as elasticity increases, the number of neurons adhering on the surface decreases. Notably, the small-world coefficient - a topological measure of networks - also decreases. Numerical simulations and functional multi-calcium imaging experiments further indicated that the activity of neuronal cells on soft surfaces improves for decreasing E. Experimental findings are supported by a mathematical model, that explains adhesion and clustering of cells on soft materials as a function of few parameters - including the Young's modulus and roughness of the material. Overall, results indicate that - in the considered elasticity interval - increasing the compliance of a material improves adhesion, improves clustering, and enhances communication of neurons.

Hydrogel particles-on-chip (HyPoC): a fluorescence micro-sensor array for IgG immunoassay

Novel microparticles have generated growing interest in diagnostics for potential sensitivity and specificity in biomolecule detection and for the possibility to be integrated in a micro-system array as a lab-on-chip. Indeed, bead-based technologies integrated in microfluidics could speed up incubation steps, reduce reagent consumption and improve accessibility of diagnostic devices to non-expert users. To limit non-specific interactions with interfering molecules and to exploit the whole particle volume for bioconjugation, hydrogel microparticles, particularly polyethylene glycol-based, have emerged as promising materials to develop high-performing biosensors since their network can be functionalized to concentrate the target and improve detection. However, the limitations in positioning, trapping and mainly fine manipulation of a precise number of particles in microfluidics have largely impaired point-of-care applications. Herein, we developed an on-chip sandwich immunoassay for the detection of human immunoglobulin G in biological fluids. The detection system is based on finely engineered cleavable PEG-based microparticles, functionalized with specific monoclonal antibodies. By changing the particle number, we demonstrated tuneable specificity and sensitivity (down to 3 pM) in serum and urine. Therefore, a controlled number of hydrogel particles have been integrated in a microfluidic device for on-chip detection (HyPoC) allowing for their precise positioning and fluid exchange for incubation, washing and target detection. HyPoC dramatically decreases incubation time from 180 minutes to one minute and reduces washing volumes from 3.5 ml to 90 μL, achieving a limit of detection of 0.07 nM (with a dynamic range of 0.07-1 nM). Thus, the developed approach represents a versatile, fast and easy point-of-care testing platform for immunoassays.

Direct, precise, enzyme-free detection of miR-103–3p in real samples by microgels with highly specific molecular beacons

Low abundance, small size, and sequence similarities render microRNA (miRNAs) detection challenging, particularly in real samples, where quantifying weakly expressed miRNAs can be arduous due to interference of more abundant molecules. The standard quantitative reverse transcription polymerase chain reaction (qRT-PCR) requires multiple steps, thermal cycles, and costly enzymatic reactions that can negatively affect results. Here we present a direct, precise, enzyme-free assay based on microgels particles conjugating molecular beacons (MB) capable of optically detecting low abundant miRNAs in real samples. We validate the applicability of microgels assay using qRT-PCR as a reference technology. As a relevant case, we chose miR-103-3p, a valuable diagnostic biomarker for breast cancer, both in serum samples and MCF7 cells. As a result, microgels assay quantifies miRNA molecules at room temperature in a single step, 1 h (vs. 4 hrs for qRT-PCR) without complementary DNA synthesis, amplification, or expensive reagents. Microgels assay exhibits femtomolar sensitivity, single nucleotide specificity, and a wide linear range (10²-10⁷ fM) (wider than qRT-PCR), with low sample consumption (2 μL) and excellent linearity (R²= 0.98). To test the selectivity of the microgel assay in real samples, MCF7 cells were considered where the pool of 8 other miRNAs were further upregulated with respect to miRNA 103-3p. In such complex environments, microgels assay selectively detects the miRNA target, mainly due to MB advanced stability and specificity as well as high microgel antifouling properties. These results show the reliability of microgels assay to detect miRNAs in real samples.

PEG-based Cleavable Hydrogel Microparticles with controlled porosity for permiselective trafficking of biomolecular complexes in biosensing applications

In the last decade, PEG-based hydrogels have been extensively used for the production of microparticles for biosensing applications. The biomolecule accessibility and mass transport rate represent key parameters for the...

Hydrogel Microparticles for Fluorescence Detection of miRNA in Mix-Read Bioassay

Herein we describe the development of a mix-read bioassay based on a three-dimensional (3D) poly ethylene glycol-(PEG)-hydrogel microparticles for the detection of oligonucleotides in complex media. The key steps of hydrogels synthesis and molecular recognition in a 3D polymer network are elucidated. The design of the DNA probes and their density in polymer network were opportunely optimized. Furthermore, the diffusion into the polymer was tuned adjusting the polymer concentration and consequently the characteristic mesh size. Upon parameters optimization, 3D-PEG-hydrogels were synthetized in a microfluidic system and provided with fluorescent probe. Target detection occurred by double strand displacement assay associated to fluorescence depletion within the hydrogel microparticle. Proposed 3D-PEG-hydrogel microparticles were designed for miR-143-3p detection. Results showed 3D-hydrogel microparticles with working range comprise between 10-6-10-12 M, had limit of detection of 30 pM and good specificity. Moreover, due to the anti-fouling properties of PEG-hydrogel, the target detection occurred in human serum with performance comparable to that in buffer. Due to the approach versatility, such design could be easily adapted to other short oligonucleotides detection.

Easy Surface Functionalization and Bioconjugation of Peptides as Capture Agents of a Microfluidic Biosensing Platform for Multiplex Assay in Serum

The development of assays for protein biomarkers in complex matrices is a demanding task that still needs implementation of new approaches. Antibodies as capture agents have been largely used in bioassays but their low stability, low-efficiency production, and cross-reactivity in multiplex approaches impairs their larger applications. Instead, synthetic peptides, even with higher stability and easily adapted amino acid sequences, still remain largely unexplored in this field. Here, we provide a proof-of-concept of a microfluidic device for direct detection of biomarker overexpression. The multichannel microfluidic polydimethylsiloxane (PDMS) device was first derivatized with PAA (poly(acrylic acid)) solution. CRP-1, VEGF-114, and ΦG6 peptides were preliminarily tested to respectively bind the biomarkers, C-reactive protein (CRP), vascular endothelial growth factor (VEGF), and tumor necrosis factor-alpha (TNF-α). Each PDMS microchannel was then respectively bioconjugated with a specific peptide (CRP-1, VEGF-114, or ΦG6) to specifically capture CRP, VEGF, and TNF-α. With such microdevices, a fluorescence bioassay has been set up with sensitivity in the nanomolar range, both in buffered solution and in human serum. The proposed multiplex assay worked with a low amount of sample (25 μL) and detected biomarker overexpression (above nM concentration), representing a noninvasive and inexpensive screening platform.

Small Oligonucleotides Detection in Three-Dimensional Polymer Network of DNA-PEG Hydrogels

The control of the three-dimensional (3D) polymer network structure is important for permselective materials when specific biomolecule detection is needed. Here we investigate conditions to obtain a tailored hydrogel network that combines both molecular filtering and molecular capture capabilities for biosensing applications. Along this line, short oligonucleotide detection in a displacement assay is set within PEGDA hydrogels synthetized by UV radical photopolymerization. To provide insights on the molecular filter capability, diffusion studies of several probes (sulforhodamine G and dextrans) with different hydrodynamic radii were carried out using NMR technique. Moreover, fluorometric analyses of hybridization of DNA oligonucleotides inside PEGDA hydrogels shed light on the mechanisms of recognition in 3D, highlighting that mesh size and crowding effect greatly impact the hybridization mechanism on a polymer network. Finally, we found the best probe density and diffusion transport conditions to allow the specific oligonucleotide capture and detection inside PEGDA hydrogels for oligonucleotide detection and the filtering out of higher molecular weight molecules.

OP0256-PARE A PAW? YES, THANK YOU AN ANIMAL ASSISTED INTERVENTION (AAI) PILOT PROJECT FOR CHILDREN WITH JUVENILE IDIOPATHIC ARTHRITIS (JIA)

Background:

Animal-Assisted Interventions (AAI) is the new way to indicate what was previously known as “Pet Therapy”, as activities can be done either with the conventional “pets” (dogs, cats and rabbits) or with horses and donkeys.

Children with JIA have several problems in terms of adherence both due to the atavistic fear of the needle and due to nausea and vomiting - the most important side effects of Methotrexate – often since the 2-3 days before the assumption to immediately after it.

Sure that animals can help children to forget this fear and to avoid the psycological conditions which enhance nausea, for the first time in Italy (and probably in Europe) it was designed a specific AAI program for these children.

Objectives:

To promote a general state of psycho-physical well-being in children and families about:

manage of therapy; reduce discomfort and anxiety caused by entering hospital; improve self-esteem and the response to the stress generated by the execution of therapy and disease management; strengthen communication and socialization; stimulate the affective area through the activities of animal care.

Methods:

Dogs and cats are part of the recreational activities once a week in an equipped area in the OIRM Hospital (no alternative gateway was needed).

Paediatric Rheumatologists selected two different groups of children: the first one (5 children in the pilot study) every 15 days; the second one (5 children) every month; the selection was made looking at the therapeutic scheme.

Every session, one hour, has 3 clearly distinct stages:

Welcome and organization: children say hello to dogs and cats, open the toolkits specifically designed for the intervention, express their state of mind and are encouraged to tell their own stories.

Therapy:parents prepare and inject the drug to their children under medical or Health Professional control without discontinuation of the activities with animals.

Play and socializing:children are involved in petting and other activities with animals; they are also involved in manipulative activities (design, puppets shows, modelling clay, animal care, ball retriving, etc). This step has the aim to relieve stress and discomfort due to medical procedures.

Visual Analogic Scales (VAS) were part of the toolkit, to let the researchers evaluate the effects of the activity directly from the children experience.

For the first time, we will control also the animal health status and wellness condition monitoring behavioural parameters and salivary cortisol level during each session.

Results:

The pilot project started in October 2019 and nowaday we closed 12 meetings, 4 on October, 4 on November, 3 on December and 2 on January, with the participation of 2 dogs (Golden and Labrador Retriever) and 1 cat (Devon Rex) in each one.

All children love to play with animals, seek their closeness at the time of therapy and enjoy playing all together with the dogs; no one cry or refuse therapy and, since the third session, no one has nausea before, during or after the injection. Parents have reached a certain level of confidence: they stay quietly in the waiting room or go away to have a drink or to run an errand (it becomes a moment of relaxing for them too).

Animals remain in healthy and wellness conditions during the activity.

Conclusion:

These preliminary data seem that AAI to be useful in helping patients in JIA to overcome some problems related to their pathology.

Disclosure of Interests:

UGO VIORA: None declared, Patrizia Ponzio: None declared, Maria Teresa Mascarino: None declared, Barbara Picco: None declared, Paolo Guiso: None declared, Eleonora Battista: None declared, Silvana Martino: None declared, Davide Montin Speakers bureau: Not relevant for the topic, Marta Dellepiane: None declared, Germana Rosso: None declared

Supramolecular Microgels with Molecular Beacons at the Interface for Ultrasensitive, Amplification-Free, and SNP-Selective miRNA Fluorescence Detection

In this study, a supramolecular structure with femtomolar biorecognition properties is proposed for use in analytical devices. It is obtained by an innovative interface between synthetic hydrogel polymers and molecular beacon (mb) probes. Supramolecularly structured microgels are synthetized with a core-shell architecture with specific dyes polymerized in a desired compartment. Mb probes are opportunely conjugated at the microgel interface so that their recognition mechanism is preserved and their spatial distribution is optimized to avoid crowding effects. The miR-21, a microRNA involved in various biological processes and usually used as a biomarker in early cancer diagnosis, has been selected as the target. The results demonstrate that by tuning the spatial distribution of molecular probes immobilized on the microgel and/or the amount of microgels, the assay shows scalable sensitivity reaching a limit of detection down to about 10 fM, without amplification steps and with detection time as short as 1 h. The assay results specific toward single mutated targets, and it is stable in the presence of high-interfering oligonucleotides concentrations. The miRNA target is also detected in human serum with performances similar to those observed in PBS buffer because of microgel antifouling properties without the need of any surface treatment. All tests were performed in a low sample volume (20 μL). As a result, mb-microgel represents an innovative biosensor to precisely quantify microRNAs in a direct (mix&read), scalable, and selective way. Such an approach paves the way for creating innovative biosensing interfaces with other probes, such as hairpins, aptamers, and PNA.

Biosensor for Point-of-Care Analysis of Immunoglobulins in Urine by Metal Enhanced Fluorescence from Gold Nanoparticles

Biosensors are easy-to-use and cost-effective devices that are emerging as an attractive tool, not only in settling diagnosis or in disease monitoring, but also in mass screening tests, a timely topic that impacts on daily life of the whole society. Nanotechnologies lend themselves to the development of highly sensitive devices whose realization has become a very interdisciplinary topic. Relying on the enhancement of the fluorescence signal detected at the surface of patterned gold nanoparticles, we report the behavior of an analytical device in detecting immunoglobulins in real urine samples that shows a limit of detection of approximately 8 μg/L and a linear range of 10-100 μg/L well below the detection limit of nephelometric method, which is the reference method for this analysis. These performances have been reached thanks to an effective surface functionalization technique and can be improved even more if superydrophobic features of the substrate we produce will be exploited. Since the analyte recognition is realized by antibodies the specificity is very high and, in fact, no interference has been detected by other compounds also present in the real urine samples. The device has been assessed on serum samples by comparing IgG concentrations values obtained by the biosensor with those provided by a nephelometer. In this step we found that our approach allows the analysis of the whole blood without any pretreatment; moreover, it is inherently extendable to the analysis of most biochemical markers in biological fluids.

One-step scalable fluorescent microgel bioassay for the ultrasensitive detection of endogenous viral miR-US4-5p

Human cytomegalovirus (hCMV) infection is the leading cause of birth defects in newborns and death in immunosuppressed people. Traditional techniques require time-consuming and costly analyses, and sometimes result in false positive results; thus, a rapid and accurate detection for hCMV infection is necessary. Recently, hcmv-miR-US4-5p was selected as the biomarker for cytomegalovirus diagnosis and follow-up. Herein, we propose a bioassay based on microgels endowed with optical fluorescent oligonucleotide probes for the detection of circulating endogenous hcmv-microRNAs. In particular, a double strand probe, based on the fluorescence recovery after target capture, was conjugated on microgels and the probe density was opportunely optimised. Then, the microgels were directly mixed with the sample. The fluorescence read-out was measured as a function of target concentration at a fixed number of microgels per tube. As a bead-based assay, the performances of optical detection in terms of dynamic working range and limit of detection could be finely tuned by tuning the number of microgels per tube. The limit of detection of the assay could be tuned in the range from 39.1 fM to 156 aM by changing the microgel concentration from 50 μg mL^-1 to 0.5 μg mL^-1, respectively. The assay results specific for the selected target were stable over a one-year time span and they were not affected by the presence of human serum. Therefore, this bioassay based on microgels might represent a flexible platform that should be able to predict, identify and follow-up several diseases by monitoring freely circulating oligonucleotides in body fluids.

Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications

Diatom shells are a natural, theoretically unlimited material composed of silicon dioxide, with regular patterns of pores penetrating through their surface. For their characteristics, diatom shells show promise to be used as low cost, highly efficient drug carriers, sensor devices or other micro-devices. Here, we demonstrate diatom shells functionalized with gold nanoparticles for the harvesting and detection of biological analytes (bovine serum albumin-BSA) and chemical pollutants (mineral oil) in low abundance ranges, for applications in bioengineering, medicine, safety, and pollution monitoring.

Preparation and Characterization of Magnetic and Porous Metal-Ceramic Nanocomposites from a Zeolite Precursor and Their Application for DNA Separation

In this work, metal-ceramic nanocomposites were obtained through short (up to 2 h) thermal treatments at relatively moderate temperatures (750–800 °C) under a reducing atmosphere, using Fe-exchanged zeolite A as the precursor. The as-obtained materials were characterized by X-ray powder diffraction analysis, N2 adsorption at –196 °C, and highresolution transmission electron microscopy. The results of these analyses showed that the nanocomposites consisted of a dispersion of metallic Fe nanoparticles within a porous ceramic matrix, mainly based on amorphous silica and alumina. These nanocomposites were magnetically characterized, and their magnetic response was studied. Finally, the obtained metal-ceramic nanocomposite materials were used in the separation of Escherichia coli DNA from a crude cell lysate. The results of the DNA separation experiments showed that the obtained materials could perform this type of separation.

Turn-on fluorescence detection of protein by molecularly imprinted hydrogels based on supramolecular assembly of peptide multi-functional blocks

Synthetic receptors for biomacromolecules lack the supramolecular self-assembly behavior typical of biological systems. Here we propose a new method for the preparation of protein imprinted polymers based on the specific interaction of a peptide multi-functional block with a protein target. This peptide block contains a protein-binding peptide domain, a polymerizable moiety at the C-terminus and an environment-sensitive fluorescent molecule at the N-terminus. The method relies on a preliminary step consisting of peptide/protein supramolecular assembly, followed by copolymerization with the most common acrylate monomers (acrylamide, acrylic acid and bis-acrylamide) to produce a protein imprinted hydrogel polymer. Such a peptide block can function as an active assistant recognition element to improve affinity, and guarantees its effective polymerization at the protein/cavity interface, allowing for proper placement of a dye. As a proof of concept, we chose Bovine Serum Albumin (BSA) as the protein target and built the peptide block around a BSA binding dodecapeptide, with an allyl group as the polymerizable moiety and a dansyl molecule as the responsive dye. Compared to conventional approaches these hydrogels showed higher affinity (more than 45%) and imprinted sensitivity (about twenty fold) to the target, with a great BSA selectivity with respect to ovalbumin (α = 1.25) and lysozyme (α = 6.02). Upon protein binding, computational and experimental observations showed a blue shift of the emission peak (down to 440 nm) and an increase of fluorescence emission (twofold) and average lifetime (Δτ = 4.3 ns). Such an approach generates recognition cavities with controlled chemical information and represents an a priori method for self-responsive materials. Provided a specific peptide and minimal optimization conditions are used, such a method could be easily implemented for any protein target.

Molecularly endowed hydrogel with an in silico-assisted screened peptide for highly sensitive small molecule harvesting

Schematic representation of in silico-assisted screening of an AFM1 binding peptide and the working principle of toxin harvesting by molecularly endowed hydrogel.

Bioengineering Microgels and Hydrogel Microparticles for Sensing Biomolecular Targets

Hydrogels, and in particular microgels, are playing an increasingly important role in a diverse range of applications due to their hydrophilic, biocompatible, and highly flexible chemical characteristics. On this basis, solution-like environment, non-fouling nature, easy probe accessibility and target diffusion, effective inclusion of reporting moieties can be achieved, making them ideal substrates for bio-sensing applications. In fact, hydrogels are already successfully used in immunoassays as well as sensitive nucleic acid assays, also enabling hydrogel-based suspension arrays. In this review, we discuss key parameters of hydrogels in the form of micron-sized particles to be used in sensing applications, paying attention to the protein and oligonucleotides (i.e., miRNAs) targets as most representative kind of biomarkers.

Self-assembly of gold nanowire networks into gold foams: production, ultrastructure and applications

Fine-tuning the shape of nanostructured materials through easy and sustainable methods is a challenging task for green nanotechnology.

In-flow real-time detection of spectrally encoded microgels for miRNA absolute quantification

We present an in-flow ultrasensitive fluorescence detection of microRNAs (miRNAs) using spectrally encoded microgels. We researched and employed a viscoelastic fluid to achieve an optimal alignment of microgels in a straight measurement channel and applied a simple and inexpensive microfluidic layout, allowing continuous fluorescence signal acquisitions with several emission wavelengths. In particular, we chose microgels endowed with fluorescent emitting molecules designed for multiplex spectral analysis of specific miRNA types. We analysed in a quasi-real-time manner circa 80 microgel particles a minute at sample volumes down to a few microliters, achieving a miRNA detection limit of 202 fM in microfluidic flow conditions. Such performance opens up new routes for biosensing applications of particles within microfluidic devices.

High sensitive and direct fluorescence detection of single viral DNA sequences by integration of double strand probes onto microgels particles

A novel class of probes for fluorescence detection was developed and combined to microgel particles for a high sensitive fluorescence detection of nucleic acids.

Large-Scale Plasmonic nanoCones Array For Spectroscopy Detection

Advanced optical materials or interfaces are gaining attention for diagnostic applications. However, the achievement of large device interface as well as facile surface functionalization largely impairs their wide use. The present work is aimed to address different innovative aspects related to the fabrication of large-area 3D plasmonic arrays, their direct and easy functionalization with capture elements, and their spectroscopic verifications through enhanced Raman and enhanced fluorescence techniques. In detail, we have investigated the effect of a Au-based nanoCone array, fabricated by means of direct nanoimprint technique over large area (mm(2)), on protein capturing and on the enhancement in optical signal. A selective functionalization of gold surfaces was proposed by using a peptide (AuPi3) previously selected by phage display. In this regard, two different sequences, labeled with fluorescein and biotin, were chemisorbed on metallic surfaces. The presence of Au nanoCones array consents an enhancement in electric field on the apex of cone, enabling the detection of molecules. We have witnessed around 12-fold increase in fluorescence intensity and SERS enhancement factor around 1.75 × 10(5) with respect to the flat gold surface. Furthermore, a sharp decrease in fluorescence lifetime over nanoCones confirms the increase in radiative emission (i.e., an increase in photonics density at the apex of cones).

Surface decoration with gH625-membranotropic peptides as a method to escape the endo-lysosomal compartment and reduce nanoparticle toxicity

The membranotropic peptide gH625 is able to transport different cargos (i.e., liposomes, quantum dots, polymeric nanoparticles) within and across cells in a very efficient manner. However, a clear understanding of the detailed uptake mechanism remains elusive. In this work, we investigate the journey of gH625-functionalized polystyrene nanoparticles in mouse-brain endothelial cells from their interaction with the cell membrane to their intracellular final destination. The aim is to elucidate how gH625 affects the behavior of the nanoparticles and their cytotoxic effect. The results indicate that the mechanism of translocation of gH625 dictates the fate of the nanoparticles, with a relevant impact on the nanotoxicological profile of positively charged nanoparticles.

Integration of binding peptide selection and multifunctional particles as tool-box for capture of soluble proteins in serum

In this paper, we report on a general approach for the detection of a specific tumoural biomarker directly in serum. Such detection is made possible using a protein-binding peptide selected through an improved phage display technique and then conjugated to engineered microparticles (MPs). Protein biomarkers represent an unlimited source of information for non-invasive diagnostic and prognostic tests; MP-based assays are becoming largely used in manipulation of soluble biomarkers, but their direct use in serum is hampered by the complex biomolecular environment. Our technique overcomes the current limitations as it produces a selective MP--engineered with an antifouling layer--that 'captures' the relevant protein staying impervious to the background. Our system succeeds in fishing-out the human tumour necrosis factor alpha directly in serum with a high selectivity degree. Our method could have great impact in soluble protein manipulation and detection for a wide variety of diagnostic applications.

A method to tune the shape of protein-encapsulated polymeric microspheres

Protein encapsulation technologies of polymeric microspheres currently in use have been optimized to effectively protect their “protein cargo” from inactivation occurring in biological environments, preserving its bioactivity during release up to several weeks. The scenario of protein delivery would greatly benefit by strategies enabling the production of non-spherical particles. Herein we report an easy and effective stamp-based method to produce poly-lactic-glycolic-acid (PLGA) microparticles encapsulating Vascular Endothelial Growth Factor (VEGF) of different shapes. We demonstrate that PLGA microspheres can be deformed at room temperature exploiting solvent/non-solvent plasticization in order to preserve the properties of the starting microspheres. This gentle method allows the production of shaped particles that provide a prolonged release of VEGF in active form, as verified by an angiogenic assay. The retention of the biological activity of an extremely labile molecule, i.e. VEGF, lets us hypothesize that a wide variety of drug and protein encapsulated polymeric microspheres can be processed using this method.

Thermoresponsive PNIPAAm hydrogel scaffolds with encapsulated AuNPs show high analyte-trapping ability and tailored plasmonic properties for high sensing efficiency

The preparation of thermoresponsive PNIPAAm hydrogel scaffolds with encapsulated AuNPs showed high analyte-trapping ability and tailored plasmonic properties with high sensing efficiency.

Microstructure, degradation and in vitro MG63 cells interactions of a new poly(ε-caprolactone), zein, and hydroxyapatite composite for bone tissue engineering

Novel biodegradable biomaterials were investigated for potential application in bone tissue engineering. The biomaterials were prepared by blending poly(ε-caprolactone) and thermoplastic zein, a corn protein, with or without the incorporation of hydroxyapatite particles. The biomaterials were characterized in vitro to assess the degradation in phosphate buffer saline for 56 days by monitoring weight change, morphology, wettability, and tensile properties. The interaction between the biomaterials and MG63 was evaluated by proliferation, morphological characterization, and osteogenic differentiation assays up to 28 days in in vitro cultures. The incorporation of thermoplastic zein within poly(ε-caprolactone) enhanced the hydrophilicity and degradability, while minor effects were observed after the inclusion of the hydroxyapatite particles. Compared to the neat poly(ε-caprolactone), the multiphase poly(ε-caprolactone)/thermoplastic zein–hydroxyapatite composite improved the osteogenic differentiation of MG63 cells and is being considered a candidate material for bone tissue engineering applications.

Surface investigation on biomimetic materials to control cell adhesion: the case of RGD conjugation on PCL

The cell recognition of bioactive ligands immobilized on polymeric surfaces is strongly dependent on ligand presentation at the cell/material interface. While small peptide sequences such as Arg-Gly-Asp (RGD) are being widely used to obtain biomimetic interfaces, surface characteristics after immobilization as well as presentation of such ligands to cell receptors deserve more detailed investigation. Here, we immobilized an RGD-based sequence on poly(epsilon-caprolactone) (PCL), a largely widespread polymeric material used in biomedical applications, after polymer aminolysis. The surface characteristics along with the efficacy of the functionalization was monitored by surface analysis (FTIR-ATR, contact angle measurements, surface free energy determination) and spectrophotometric assays specially adapted for the analytical quantification of functional groups and/or peptides at the interface. Particular attention was paid to the evaluation of a number, morphology, and penetration depth of immobilized functional groups and/or peptides engrafted on polymeric substrates. In particular, a typical morphology in peptide distribution was evidenced on the surface raised from polymer crystallites, while a significant penetration depth of the engrafted molecules was revealed. NIH3T3 fibroblast adhesion studies verified the correct presentation of the ligand with enhanced cell attachment after peptide conjugation. Such work proposes a morphological and analytical approach in surface characterization to study the surface treatment and the distribution of ligands immobilized on polymeric substrates.

Proglumide as a morphine adjunct in cancer pain management

Proglumide, a cholecystokinin (CCK) antagonist, has been shown to have agonist effects at extremely low doses on both endogenous and exogenous opioid systems. To determine the effectiveness and the side effects of proglumide as an opioid agonist, a double-blind crossover study was conducted in 60 patients with cancer pain who were treated with opioid analgesics. Forty-three patients completed both treatment arms: (a) full analgesic dose plus placebo (the patient's usual analgesic dose, individualized to drug dose and route) and (b) one-half analgesic dose plus 50 mg of proglumide. An analysis of eight pain descriptors was performed to determine whether or not these treatments were associated with a difference in patients' pain perception. The level of patient anxiety differed between the two arms, but was inconsistent over time. There were no side effects detected with proglumide, as determined by clinical monitoring and patient questionnaire. No differences in pain perception were detected between the study arms. The latter finding is consistent with an augmentation of morphine analgesia, but without additional controls, the equivalency of the two arms cannot be determined with certainty. Nonetheless, this study suggests that proglumide may have use as an opioid adjunct in patients with cancer pain.

Consenting to DNR: critical care nurses' interactions with patients and family members

OBJECTIVE: To investigate the process of consenting to do-not-resuscitate status from the perspective of critical care nurses who have been involved with patients and/or family members during their decision. METHOD: A network sample of 22 critical care nurses, with at least 1 year's experience in a critical care unit and self-reported multiple experiences with the do-not-resuscitate consent process, participated in the study. Semistructured, formal interviews were used to collect data. All interviews were tape recorded and transcribed verbatim. The grounded theory method was used to collect and analyze data. RESULTS: The analysis revealed a core category: consenting to do-not-resuscitate status. Integrated into the process were intervening conditions that further explained the process: the meaning of "do not resuscitate," the importance of time/timing in the process, the nurse's role and conflict issues that arose during the process of consenting to do-not-resuscitate status. CONCLUSIONS: The theoretical model developed in this study provides a framework to describe the role of critical care nurses in the do-not-resuscitate process. In addition, a description of the categories provides information for nurses, especially novice nurses, to consider when caring for patients and families who are in the process of making decisions concerning resuscitation.

Consenting to DNR: critical care nurses' interactions with patients and family members

OBJECTIVE

To investigate the process of consenting to do-not-resuscitate status from the perspective of critical care nurses who have been involved with patients and/or family members during their decision.

METHOD

A network sample of 22 critical care nurses, with at least 1 year's experience in a critical care unit and self-reported multiple experiences with the do-not-resuscitate consent process, participated in the study. Semistructured, formal interviews were used to collect data. All interviews were tape recorded and transcribed verbatim. The grounded theory method was used to collect and analyze data.

RESULTS

The analysis revealed a core category: consenting to do-not-resuscitate status. Integrated into the process were intervening conditions that further explained the process: the meaning of "do not resuscitate," the importance of time/timing in the process, the nurse's role and conflict issues that arose during the process of consenting to do-not-resuscitate status.

CONCLUSIONS

The theoretical model developed in this study provides a framework to describe the role of critical care nurses in the do-not-resuscitate process. In addition, a description of the categories provides information for nurses, especially novice nurses, to consider when caring for patients and families who are in the process of making decisions concerning resuscitation.