Search

Nature's material systems during evolution have developed the ability to respond and adapt to environmental stimuli through the generation of complex structures capable of varying their functions across direction, distances and time. 3D printing technologies can recapitulate structural motifs present in natural materials, and efforts are currently being made on the technological side to improve printing resolution, shape fidelity, and printing speed. However, an intrinsic limitation of this technology is that printed objects are static and thus inadequate to dynamically reshape when subjected to external stimuli. In recent years, this issue has been addressed with the design and precise deployment of smart materials that can undergo a programmed morphing in response to a stimulus. The term 4D printing was coined to indicate the combined use of additive manufacturing, smart materials, and careful design of appropriate geometries. In this review, we report the recent progress in the design and development of smart materials that are actuated by different stimuli and their exploitation within additive manufacturing to produce biomimetic structures with important repercussions in different but interrelated biomedical areas. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the utility of nanocarriers for the transportation of gaseous signalling molecules to their target site in a biological environment is an effective approach. In this work, we have developed for the first time visible light responsive nanocarriers for the effective release of H2S. Our newly developed nanocarriers for H2S release are constructed using two main ingredients: fluorescent carbon dots and quinoline as an H2S donor. The developed nanocarriers provided interesting properties like good solubility under physiological conditions, excellent fluorescence properties and efficient release ability of H2S with good quantum yield upon visible light irradiation. In vitro studies revealed that our designed nanocarriers exhibited abilities like efficient cellular internalization and good biocompatibility. [ABSTRACT FROM AUTHOR]

A series of spherical magneto-responsive nanogels were fabricated by formulating different sets of star block copolymers based on pentaerythritol–poly(ε-caprolactone)-b-poly(acrylic acid) (PE–PCL-b-PAA) combined with amine-functionalized magnetic nanoparticles for targeted cancer therapy. Superparamagnetic nanoparticles, Fe3O4 (5 ± 0.5 nm), were modified with (3-aminopropyl)trimethoxysilane to introduce the amine functionality into the system which also imparts colloidal stability. In the star block copolymer, the hydrophilic PAA chain length has an architecture such that it can accommodate a large number of amine-functionalized magnetic nanoparticles. The hydrodynamic size of the nanogel has been observed in the range of 65 ± 2 nm to 616 ± 7 nm. The as-prepared nanogel has been employed to deliver an anticancer drug, doxorubicin (DOX). A maximum of 20% of DOX encapsulation has been observed. In the presence of physiological pH of cancer cells (pH 5), the nanogel is able to deliver 73% of drug in 24 h which is further enhanced in the presence of an external static magnetic field (76% release). Under the influence of a high-frequency alternating magnetic field the in vitro drug release rate is 56% h−1. The low viscosity (0.21 Pa s) at high shear rate (1000 s−1) makes the nanogel suitable for painless injection. The pristine nanogel shows about 80% cell viability against the C6 glioma cell line. The magnetic field-induced targeting effect (cell uptake) of the fabricated nanogel has been visualized by fluorescence confocal microscopy. The therapeutic effect of the DOX-loaded nanogel has been examined against the C6 glioma cell line and it is found that the DOX-loaded magnetic nanogel having a composition of PE–PCL20-b-PAA180 with 10% amine-modified Fe3O4 shows selectively high toxic (IC50 = 3.85 μg mL−1) effect towards the C6 glioma cell line. This kind of new class of magnetic nanogel can open a new direction for MRI-guided drug delivery systems. [ABSTRACT FROM AUTHOR]

A water-soluble dilithium salt BODIPY derivative (LiBDP) with appended dicarboxylate pseudo-crown ether [NO4] coordinating sites has been designed, synthesized and characterized successfully for the selective and sensitive recognition of Cd2+ in aqueous media. The chemosensor exhibits a remarkable increase in fluorescence intensity as well as a distinct color change upon the addition of Cd2+ over other environmentally and biologically relevant metal ions in H2O. The fluorometric response of LiBDP is attributed to the metal chelation-enhanced fluorescence (MCHEF) effect which has been confirmed by a strong association constant of 2.57 ± 1.06 × 105 M−1 and Job's plot, indicating 1 : 1 binding stoichiometry between LiBDP and Cd2+. Frontier molecular orbital analysis (obtained from DFT studies) also illustrates the turn-on fluorescence of the probe by blocking photoinduced electron transfer (PET) after coordination to Cd2+. The probe can detect Cd2+ in a competitive environment up to a submicromolar level in a biologically significant pH range. The sensor is proved to be reversible and reusable by the alternative addition of Cd2+ followed by S2−. The OFF/ON/OFF sensing behavior is utilized to construct an INHIBIT molecular logic gate based on the two inputs of Cd2+ and S2− and a fluorescence intensity at 512 nm as an output. The test paper experiment demonstrates the practical utility of LiBDP to monitor Cd2+ in an aqueous sample. Finally, the sensing probe was utilized to monitor Cd2+ in living cells. [ABSTRACT FROM AUTHOR]

We investigate the deformation characteristics of red blood cells (RBCs) on a rotating compact disc platform. Our study brings out the interplay between haemoglobin content and RBC deformability in a centrifugally actuated microfluidic environment. We reveal that RBC deformations follow the similar trend of principal stress distributed throughout the radial direction, rendering an insight into the mechano-physical processes involved. This study can be used as a diagnostic marker to determine haematological disorders in diseased blood samples tested on compact disc based microfluidic platforms. [ABSTRACT FROM AUTHOR]

We demonstrate capillarity-driven plasma separation from whole blood on simple paper-based H-channels. This methodology, unlike other reported techniques, does not necessitate elaborate and complex instrumentation, and the usage of expensive consumables. We believe that this technique will be ideally suited to be implemented in rapid and portable blood diagnostic devices designed to be operative at locations with limited resources. [ABSTRACT FROM AUTHOR]

We investigate blood flow dynamics on a rotationally actuated lab-on-a-compact disk (LOCD) platform, as a function of the hematocrit level of the blood sample. In particular, we emphasize the resultant implications on the critical fluidic parameters, such as on burst frequency and volumetric flow rate. Our results can be utilized as a characteristic guideline to predict the hematological parameters of a given small amount of blood sample from the observed flow characteristics, and can give rise to a new paradigm of medical diagnostics driven by interactions between blood rheology and rotational forces on an inexpensive platform, with minimal sample consumption. [ABSTRACT FROM AUTHOR]

This study focused on the design of novel mechanically tough, biocompatible, osteoconductive and biodegradable scaffolds based on sunflower oil modified hyperbranched polyurethane (HBPU)/functionalized multi-walled carbon nanotube (f-MWCNT) nanocomposites (NCs), and the response of an animal model on their post-implantation. The NC was prepared by an in situ polymerization technique with different wt% of f-MWCNTs. The tensile strength of the NCs was enhanced to 36.98–47.6 MPa from 23.93 MPa (HBPU) and toughness from 12 767 to 18 427–19 440 due to the addition and efficient dispersion of the f-MWCNTs in the HBPU matrix. The post-60 days in vitro biodegraded NC retained sufficient strength (39 ± 1.65 MPa). The increase in wt% of f-MWCNTs had a significant effect on tailoring the physico-mechanical properties of the polymer. The hematological, histological and immunological indices of toxicity suggested the safety potential of the prepared systems within the tested animal model. Moreover, the cytokines (viz. IL-6 and TNF-α) detection, MTT assay and anti-hemolytic assay boosted the non-toxic behavior of the systems. The NC with interconnected pores size (200–330 μm) showed better proliferation and adherence of osteoblast (MG63) cells compared to the HBPU and the results were comparable with the control. Thus the findings confirmed the non-toxicity of f-MWCNTs in association with the polymer and thereby endorsed the NC as a potential biomimetic scaffold for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the utility of nanocarriers for the transportation of gaseous signalling molecules to their target site in a biological environment is an effective approach. In this work, we have developed for the first time visible light responsive nanocarriers for the effective release of H 2 S. Our newly developed nanocarriers for H 2 S release are constructed using two main ingredients: fluorescent carbon dots and quinoline as an H 2 S donor. The developed nanocarriers provided interesting properties like good solubility under physiological conditions, excellent fluorescence properties and efficient release ability of H 2 S with good quantum yield upon visible light irradiation. In vitro studies revealed that our designed nanocarriers exhibited abilities like efficient cellular internalization and good biocompatibility.

A water-soluble dilithium salt BODIPY derivative (LiBDP) with appended dicarboxylate pseudo-crown ether [NO4] coordinating sites has been designed, synthesized and characterized successfully for the selective and sensitive recognition of Cd2+ in aqueous media. The chemosensor exhibits a remarkable increase in fluorescence intensity as well as a distinct color change upon the addition of Cd2+ over other environmentally and biologically relevant metal ions in H2O. The fluorometric response of LiBDP is attributed to the metal chelation-enhanced fluorescence (MCHEF) effect which has been confirmed by a strong association constant of 2.57 ± 1.06 × 105 M-1 and Job's plot, indicating 1 : 1 binding stoichiometry between LiBDP and Cd2+. Frontier molecular orbital analysis (obtained from DFT studies) also illustrates the turn-on fluorescence of the probe by blocking photoinduced electron transfer (PET) after coordination to Cd2+. The probe can detect Cd2+ in a competitive environment up to a submicromolar level in a biologically significant pH range. The sensor is proved to be reversible and reusable by the alternative addition of Cd2+ followed by S2-. The OFF/ON/OFF sensing behavior is utilized to construct an INHIBIT molecular logic gate based on the two inputs of Cd2+ and S2- and a fluorescence intensity at 512 nm as an output. The test paper experiment demonstrates the practical utility of LiBDP to monitor Cd2+ in an aqueous sample. Finally, the sensing probe was utilized to monitor Cd2+ in living cells.