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Cardiac troponins are highly sensitive and specific biomarkers for cardiac injury. Previous studies evaluating the effect of positive airway pressure (PAP) on cardiac troponins in patients with sleep-disordered breathing (SDB) have yielded conflicting results. The meta-analysis was performed to examine the effect of PAP on cardiac troponins in SDB patients.PubMed, Web of Science, and EMBASE before September 2021 on original English language studies were searched. The data on cardiac troponins in both baseline and post-PAP treatment were extracted from all studies. The data on the change of cardiac troponins in both PAP and control group were extracted from randomized controlled trials. Standardized mean difference (SMD) was used to synthesize quantitative results.A total of 11 studies were included. PAP treatment was not associated with a significant change in cardiac troponin T between the baseline and post-PAP treatment (SMD = -0.163, 95% confidence interval [CI] = -0.652 to 0.326, z = 0.65, p = .514). The pooled estimate of SMD of cardiac troponin I between the pre- and post-PAP treatment was 0.287, and the 95% CI was -0.586 to 1.160 (z = 0.64, p = .519). The pooled SMD of change of cardiac troponin T between the PAP group and control group was -0.473 (95% CI = -1.198 to 0.252, z = 1.28, p = .201).This meta-analysis revealed that PAP treatment was not associated with any change of cardiac troponin in SDB patients.

Joint replacement surgery is one of the orthopedic surgeries with high successful rates; however, wear debris generated from prostheses can ultimately lead to periprosthetic osteolysis and failure of the implant. The implant-derived particulate debris such as ultrahigh molecular weight polyethylene (UHMWPE) can initiate the local immune response and recruit monocytic cells to phagocytose particles for generating reactive oxygen species (ROS). ROS induces osteoclastogenesis and macrophages to secrete cytokines which ultimately promote the development of osteolysis. In this work, we develop the few-layered Nb2C (FNC) as an antioxidant which possesses the feature of decreasing the production of cytokines and inhibiting osteoclastogenesis by its ROS adsorption. Moreover, local injection of FNC attenuates the UHMWPE-induced osteolysis in a mouse calvarial model. In sum, our results suggest that FNC can be used for treating osteolytic bone disease caused by excessive osteoclastogenesis., Graphical abstract Image 1, Highlights • Few-layered Nb2C (FNC) was synthesized by chemical exfoliation from bulk Nb2C (BNC) and showed an outstanding elimination of ROS on the basis of density functional theory (DFT) and inhibition effect of oxidative stress in vitro. • Osteoxlastogenesis was driven by reactive oxygen species (ROS), controlling osteoclasts differentiation in the early stage. • FNC inhibited osteoclastogenesis via scavenging ROS and dampening related signal pathway. • UHMWPE-induced osteolysis was attenuated by FNC therapy.

Graphitic carbon nitride (g-C3N4) is a two-dimensional (2D) photocatalyst, but it appears a mediocre catalytic property due to the recombination of charge carriers. Constructing heterojunctions can boost the separation and suppress the recombination of photo-generated electron–hole pairs. For the conventional Type-II heterojunction, the oxidation ability is significantly reduced due to the decreasing of band gap. We try to maintain its oxidation capacity and promote the artificial bandgap by tailoring a Z-scheme heterojunction through interface engineering. Herein, we grafted different proportions of YMnO3 3D-nanoparticles onto g-C3N4 2D-nanosheets. This special 2D/3D mixed-dimensional nanocomposite exhibits efficient charge carrier transport performance according to the electrochemistry and photocurrent measurement. The outstanding photocatalytic oxidation ability can be verified by the rate of Rhodamine B degradation, which is 3.8 and 2.3 times of YMnO3 and g-C3N4, respectively. Theoretical calculation, active group capture experiments and electron spin resonance indicate the energy band position and the reactive groups (superoxide radicals and holes). The optimized g-C3N4/YMnO3 heterojunction utilizes the interfacial synergistic effect to achieve a composition of vigorous oxidizing ability and outstanding visible light harvesting. This work will pave a promising access for mechanism and interface engineering of other g-C3N4-based Z-scheme heterojunctions.

A typical multiferroic manganese oxide of HoMnO3 was partially substituted by Fe at Mn site. Orthogonal crystalline phase of HoMn1−xFexO3 was synthesized at normal pressure. This finding has changed the conventional method of synthesizing orthogonal crystalline phase of rare-earth manganese oxides under high-temperature and high-pressure. The doping of iron ions suppresses the formation of hexagonal phase as revealed from X-ray diffraction, Morphology analysis, Raman spectrum and X-ray photoelectron spectroscopy. The doping of Fe3+ into HoMnO3 causes changes in the space group of the sample and ferroelectricity at room temperature. There are two phases with a ferroelectric space group of $${P6}_{3}cm$$ and a paraelectric one of Pnma coexisted in Ho $${\text{Mn}}_{1-x}{Fe}_{x}{O}_{3}$$ polycrystalline with x 0.15, the phase with $${P6}_{3}cm$$ space group disappears, and samples have only one crystalline phase Pnma. We found that the sample remained ferroelectricity at room temperature in the process of changing the doping concentration. The ferroelectric property disappears until it completely changed to the orthogonal phase. The synthesis of orthogonal HoMnO3 at normal pressure has not been previously reported and potentially open up abroad research and application prospects.

Molecular ferroelectrics are a kind of functional materials that have large application prospects. Comparing with the traditional inorganic ferroelectrics, they have some advantages, such as easy design, environment-friendliness, nontoxicity, and flexibility. In this study, a new molecular ferroelectric pyridin-2-ylmethanaminium perchlorate was discovered, which undergoes a ferroelectric phase transition at around 264.8 K. The spontaneous polarization reaches 0.22 μC cm−2, and the coercive fields are as small as 1.1 kV cm−1 at 202 K. The single-crystal X-ray diffraction analysis reveals that the space group transforms from a polar space group of P21 at 173 K to a centrosymmetric space group of P21/c at 293 K. By analyzing the crystal structure changes below and above the phase transition temperature, it can be concluded that the phase transition is induced by the disorder of perchlorate. Its ferroelectricity was confirmed by the measurements of differential scanning calorimetry, dielectric and hysteresis loop.

Transition metal oxide nanomaterials (TMOs) have been adopted to produce reactive oxygen species (ROS) and adjust tumor microenvironment (TME) in cancer therapy. However, mono-modal treatment and the incompatibility of biological enzyme both hampered the therapeutic effect. Herein, we developed a multimodal TMO-based nanoplatform that the ultrathin Ti3C2 nanosheets were attached onto the MnFe2O4 nanoparticles self-assembled by applying chitosan as a chemical crosslinker to construct an interfacial Schottky junction, Ti3C2@Chitosan-MnFe2O4 (TC@Ch-MFO), achieving improved ROS generation as well as optimized biocompatibility. This heterojunction can controllably catalyze hydrogen peroxide (H2O2) to generate O2 and deplete the overexpressed glutathione (GSH) levels in hypoxic TME, which realizes the chemodynamic therapy (CDT) by cyclized Fenton reaction under NIR excitation. TC@Ch-MFO also constructs a multimodal treatment nanoplatform by introducing available high-efficiency photothermal agent (PTA), Ti3C2, for phtotheraml therapy (PTT). In addition, it simultaneously integrates the visualization with T1- and T2-weighting magnetic resonance imaging (MRI). The toxicity of TC@Ch-MFO to normal tissue cells is negligible. This platform could provide new insights into the development of multimoded synergistic nanoplatform for biological applications, especially breaking the shackles of MXenes merely used as a photo-thermal agent, adopting it to bioimaging sensor and drug loading.

The use of 2-naphthalenesulfonate (NAS) ligand in lanthanide chemistry afforded a family of isostructural mononuclear lanthanide complexes with the formula [Ln(NAS)2(H2O)6](NAS)·3H2O [Ln = Tb (1), Dy (2), Er (3), Yb (4)]. Crystallographic studies determined a square antiprismatic geometry (D4d) for the Ln centre and crystallization in an unprecedented chiral space group. The latter was further confirmed by the observation of Cotton effects in single crystal circular dichroism (CD) spectra. Static and dynamic magnetic measurements identified weak intermolecular dipolar interactions in 2, and such effects can be waived by dilution, which was noted by the detection of zero-field single molecule magnet (SMM) behaviour and hysteresis loop in a magnetically diluted sample (5). Compounds 2-4 exhibit SMM behaviours with energy barriers of 53, 32, and 45 K, respectively. To the best of our knowledge, these complexes are the first examples of pure 4f sulfonate-based SMMs.

A new molecular ferroelectric is discovered in an organic–inorganic hybrid compound, (C6H5NH3)2CdCl4, which undergoes a reversible order–disorder ferroelectric phase transition at 369 K and has a spontaneous polarization of about 0.5 μC cm−2, larger than the Rochelle salt. Large dielectric anomaly, pyroelectricity and P–E hysteresis loop were observed to represent the ferroelectricity of the compound. Especially, the dielectric constant at the transition temperature increases more than 40 times than that at room temperature, which indicates potential applications on switches and sensors for its high-temperature response and excellently reversible characterization.

Extraction or injection of charges through the interface in hybrid catalysts is a fascinating strategy for steering charge carrier transfer in solar energy conversion applications. Instead of interfacial charges regulation, we adopt intrinsic spontaneous polarization-modulated internal electric field to drive photo-generated carriers separation and transfer in both the bulk and surface for photocatalysis. Herein, we first report a series of nano-composites made of perovskite ferroelectric BiFe0.9Mn0.1O3 and orthorhombic phase α-MoO3 semiconductor (BFMO-xM, x = 0, 5%, 10%, 15%) via two-step thermal synthesis method. With × = 10%, the heterostructure exhibits significantly enhancement of optical response and photo-decomposion tetracycline capacity under sunlight compared with pure BFMO and M. The improved photocatalysis is attributed to the superimposed actions of the Z-scheme charge transfer through interface and the polarization field in BFMO for the anti-recombination of photo-excited electron-hole pairs. This work indeed offers a strategic design over multicomponent catalyst by consider the synergy of polarization charges and interfacial charge transmission for solar energy conversion.

Graphitic Carbon Nitride (g-C3N4) has extensive application prospect of photodynamic therapy (PDT), which can be attributed to the biocompatibility and photosensitivity. However, it suffers from the near-ultraviolet absorption edge and low reactive oxygen species (ROS) release rate. This work exhibits an atomic-thickness water-soluble g-C3N4 with alkali Zn2+ and K+ modification (MCN), whose absorption edge is tuned from 460 nm for GCN to the entire visible-light region (663 nm), and bandgap is reduced to 1.94 eV. Both K+- bridging intercalation and the in-plane Zn-N significantly enhance the photocatalytic performance, as well as inhibit the overexpression of glutathione (GSH) significantly. The synergistic effect make that the release rate of ROS is about 45.16 % (7.95 % for pristine g-C3N4), accomplishing a considerable inactivation efficiency of malignant melanoma A375. This work fundamentally releases the limitation of g-C3N4 as a PDT photosensitizer, revealing its multifunctional promise to cancer therapy.

We have proved that Cs2SnI6−xBrx (x = 0–6) can be eutectic in the whole composition, and the eutectic phase has the similar cubic symmetry with both of the end phases (space group of Fm3¯m). The lattice constant decreases from around 11.67 A (x = 0) to around 10.83 A (x = 6). Hall-plot analysis shows that the strain varies sharply near the two end materials, while the strain is almost independent of Br content at the middle Br content. The bandgap, on the other hand, increases from 1.26 eV to 2.93 eV with increasing the Br content, which might be expected in fabricating the continuous junction solar cells.

Two mononuclear Dy(III) compounds formulated as [Dy(PNO)6(H2O)2]Br3 (1) and [Dy(PNO)6(NO3)](ClO4)2 (2) have been synthesized and characterized. Single crystal X-ray diffraction studies show that chiral and kryptoracemic strcuctures are formed when different anions are introduced into the system. 1 crystallizes in the non-polar orthorhombic space group P212121, whereas 2 assembles as a kryptoracemate in the polar monoclinic space group P21. The optical activity of single crystals of these two compounds was confirmed by circular dichroism (CD) studies. Thermal gravimetric analyses (TGA) revealed that they are stable up to 376 K (1) and 428 K (2). Differential scanning calorimetry (DSC) measurements demonstrate the absence of structural phase transitions over the investigated temperature range. Magnetic studies show that both compounds are field-induced single molecule magnets (SMMs) with energy barriers of 36 (± 0.8) K for 1 and 32 (± 1.4) K for 2. Furthermore, the dielectric and ferroelectric properties of compound 2 were also investigated.

Two reversible first-order phase transitions were found in an improper ferroelectric, diisopropylammonium perchlorate (DIPAP), due to the crystal symmetry transforming from P21/c to P1 at 296 K, and subsequently to P21/c at 338 K in the heating process, similar to the structural transitions of the first discovered ferroelectric, Rochelle salt. The dielectric behavior shows two remarkable dielectric step-like increases at 296 K and 338 K, characteristic of improper ferroelectrics. The mechanism of the two improper ferroelectric phase transitions involves the transformation of diisopropylammonium cations and perchlorate anions, as confirmed by X-ray diffraction and Raman spectroscopy.

We have investigated unusual phase transitions that were triggered by chemical doping in $\mathrm{C}{\mathrm{a}}_{3}\mathrm{R}{\mathrm{u}}_{2}{\mathrm{O}}_{7}$. Our experiments showed that doping with a few percent of Mn ($g4%$) can change the quasi-two-dimensional metallic state of $\mathrm{C}{\mathrm{a}}_{3}\mathrm{R}{\mathrm{u}}_{2}{\mathrm{O}}_{7}$ into a Mott insulating state with a G-type antiferromagnetic order, but this Mott state cannot be induced by Fe doping. By combining these results with first-principles calculations, we show that lattice-orbital coupling (LOC) plays an important role in the Mott transition. Interestingly, the transition temperature ${T}_{\mathrm{MIT}}$ is found to be predetermined by a structural parameter denoted by $c/\sqrt{ab}$ at temperatures far above N\'eel temperature ${T}_{\mathrm{N}}$. This LOC-assisted Mott transition clearly contrasts with the band-filling picture. It is addressed that this type of Mott transition originates in the strong scattering centers formed by specific $3d$ dopants. The dopant-scattering picture is then applied to explain the puzzling doping effects that occur in other ruthenates and $3d$ oxides. Our findings will advance the general understanding of how the unusual properties of $4d$ correlated systems are governed by the complex interplay that occurs among the charge, spin, lattice, and orbital degrees of freedom.

Ferroelectrics undergoes a reversible structural phase from the ferroelectric phase to the paraelectric phase when its temperature exceeds the critical temperature namely Curie temperature Tc. As ferro-paraelectric phase transition is always accompanied by heat-flow, dielectric and pyroelectric anomaly, the value of Tc is extremely important for ferroelectrics. In this paper, the Curie temperature of lead-based perovskite ferroelectric solid solution is studied by machine learning methods including kernel ridge regression (KRR), support vector regression (SVR) and extremely randomized trees regression (ETR). We collect the Tc values of 205 different lead-based perovskites from published experimental papers, both simple perovskites with only one type of B site ion and complex perovskites with up to 5 kinds of ions in B position such as PMN-PFN-PZT are gathered. The diversity of our dataset is guaranteed for the good generalization of our model in perovskite solid solution of different complexity. The features are constructed from the physical and chemical properties of the B site elements in corresponding materials. The weighted-average and variance of the elemental properties are calculated and fed to machine learning models. We use the 5 runs of ten fold cross-validation method to evaluate the machine learning models. The hyperparameters are also chosen carefully with the cross-validation to avoid over fitting. The radial basis function kernel is used in both KRR and SVR. The insensitive error in the SVR is set to be 4 which is comparable to the random error in experiment. From our cross-validation, we find that the mean average errors (MAEs) between the predicted and experimental values of the machine learning methods are 14.4 K, 14.7 K, and 16.1 K, respectively. And the root-mean-square errors (RMSEs) are 22.5 K, 23.4 K, 23.8 K, respectively. After the optimization and the evaluation, our three machine learning models are stacked together by averaging the output of each regression model and thus building an ensemble model. The MAE of the ensemble model is 13.9 K. The RMSE of the ensemble model is 21.4 K. The predicted values keep a correlation coefficient of 0.97 with the experimental values. From the variance reduction in ETR, we derive the importance of our features when determining the Curie temperatures. The five most important factors in our ETR model are " weighted-average thermal conductivity”, " weighted-average conductivity”, " variance of specific heat capacity”, " weighted-average element number”, and " weighted-average relative atomic displacement”. We predict the Curie temperatures higher than those of 200000 types of lead-based perovskites after being trained. Now, we provide two ferroelectric materials that may have high Curie temperatures: 0.02PbMn1/2Nb1/2O3-0.98PbTiO3 (0.02PMN-0.98PT) and 0.02PbGa1/2Nb1/2-0.02PbMn1/2Nb1/2O3-0.96PbTiO3 (0.02PGN-0.02PMN-0.96PT). The predicted Curie temperatures of them are 481 ℃ and 466 ℃, respectively.

Two-dimensional (2D) systems have been widely investigated with perovskite superlattices because they show excellent epitaxy. A challenging question is naturally raised: whether lower dimensionality, e.g., one dimension (1D) and zero dimension (0D), can be achieved by perovskites? In this work, we propose a way to control the dimensionality of the octahedra network in perovskite superlattices by selecting the substrate orientation and superlattice period. Taking SrTiO3/SrRuO3 as an example, we demonstrate that the 1D structure is in a 1D Ising state, which is paramagnetic, while the 0D structure is ferromagnetic insulator with fully saturated magnetic moment on the Ru sites. New phenomena in the magnetic and electronic properties are observed, including large strain response, half-metallicity, and orbital-selective quantum confinement effects. Lower dimensional quantum materials can show peculiar magnetic or electronic properties in comparison to their bulk counterparts, yet the preparations of them are highly relying on the fabrications at nanoscales to date. A team led by Xiaoshan Wu at China's Nanjing University designed and prepared zero- and one-dimensional structures at the interface of SrTiO3/SrRuO3 with both of them having perovskite crystal structures. By pulse laser deposition at different substrate orientation, the constituent octahedral unit cells are constructed into well-organized and connected RuO6 chain- or dot-like structures, which show opposite effects on Ru magnetic moments. The entire process eliminated nano-fabrication. Manipulating dimensionality at perovskite interfaces may open an alternative yet facile way to control transport properties of oxide materials for future design of functional quantum devices.

Cations of Y and Sr co-substituting for La and Ca at A site in La2/3Ca1/3MnO3 compound, La2/3−xYxCa1/3−ySryMnO3, were synthesized successfully by solid-state reaction. X-ray diffraction shows there is only one phase with the dopants of Y and Sr within x ≤ 0.20 or y ≤ 0.19. The lattice parameters along a-, b-, and c-direction remain almost unchanged with x ≤ 0.20. The bond angle of Mn O Mn increases from 151.9° for x = 0 to 172.7° for x = 0.20 monotonically, which indicates that the Jahn–Teller effect in MnO6 octahedron decreases with increasing x. The temperature dependence of resistance with/without magnetic applied were measured and fitted theoretically. The metal-to-insulator transition temperature, TMI, decreases with increasing the Y content with x ≤ 0.10 while TMI increases slightly with further increasing x. The Y-content dependence of magnetoresistance shows a parabolic behavior. The maximum MR value corresponds to x = 0.08–0.10. We attributed these variations in the structure and transportation to the cation disorder due to the cation doping.

Modulation-doped Al0.22Ga0.78N/GaN heterostructure with 1000 angstrom Si-dopedn-A10.22Gao.78N barrier (n-AlGaN) were deposited on (0 0 0 1)-oriented sapphire (alpha-Al2O3) by means of atmosphere-pressure metal-organic chemical vapor deposition. The reciprocal space mappings of symmetric reflection (0 0 0 2) and asymmetric reflection (1 0 (1) over bar 4) were measured with high resolution X-ray diffraction. The results indicate that the microstructure and strain status of barrier correlate to that of the underlying i-GaN layer. The barrier holds an "abnormal" strain-relaxation status, which probably results from the internal defects of n-AlGaN and the strain relaxation status at the i-GaN/alpha-Al2O3 interfaces. The results from grazing incidence X-ray diffraction show that the strain in barrier is nonuniform, which is consistent with the results from the reciprocal space mappings. (c) 2005 Elsevier B.V. All rights reserved.

Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present compelling evidence that elastin, the key ECM protein found in connective tissues, is ferroelectric, and we elucidate the molecular mechanism of its switching. Nanoscale piezoresponse force microscopy and macroscopic pyroelectric measurements both show that elastin retains ferroelectricity at 473 K, with polarization on the order of 1 μC/cm(2), whereas coarse-grained molecular dynamics simulations predict similar polarization with a Curie temperature of 580 K, which is higher than most synthetic molecular ferroelectrics. The polarization of elastin is found to be intrinsic in tropoelastin at the monomer level, analogous to the unit cell level polarization in classical perovskite ferroelectrics, and it switches via thermally activated cooperative rotation of dipoles. Our study sheds light onto a long-standing question on ferroelectric switching in biology and establishes ferroelectricity as an important biophysical property of proteins. This is a critical first step toward resolving its physiological significance and pathological implications.

Human papillomavirus type 16 plays a critical role in the neoplastic transformation of cervical cancers. Molecular variants of HPV16 existing in different ethnic groups have shown substantial phenotypic differences in pathogenicity, immunogenicity and tumorigenicity. In this study, we sequenced the entire HPV16 genome of 76 isolates originated from Anyang, central China. Phylogenetic analysis of these sequences identified two major variants of HPV16 in the Anyang area, namely the European prototype (E(p)) and the European Asian type (E(As)). These two variants show a high degree of divergence between groups, and the E(p) comprised higher genetic diversity than the E(As). Analysis with two measurements of genetic diversity indicated that viral population size was relatively stable in this area in the past. Codon based likelihood models revealed strong statistical support for adaptive evolution acting on the E6 gene. Bayesian analysis identified several important amino acid positions that may be driving adaptive selection in the HPV 16 population, including R10G, D25E, L83V, and E113D in the E6 gene. We hypothesize that the positive selection at these codons might be a contributing factor responsible for the phenotypic differences in carcinogenesis and immunogenicity among cervical cancers in China based on the potential roles of these molecular variants reported in other studies.

A new organic ferroelectric compound, 4-(cyanomethyl)anilinium perchlorate, proceeds a second-order phase transition from a paraelectric phase (P2(1)/m) to a ferroelectric phase (P2(1)) at 184 K. A perfect ferroelectric hysteresis loop was observed even at 10 KHz. It is the first example of a molecule-based organic ferroelectric whose polarization can be switched at such a high frequency. The temperature dependent second harmonic generation effect shows that the second-order nonlinear coefficient is nearly zero above T(c) and proportional to the spontaneous polarization below T(c), suggesting the occurrence of symmetry breaking, in good agreement with crystal structural determination. The origin of ferroelectricity was ascribed to the displacements of -NH(3)(+) cations and ClO(4)(-) anions from the symmetric positions including a small part of the order-disorder behaviors of the ClO(4)(-) anions.

In the title compound, C8H9N+·H2PO4−, both the cation and anion have crystallographically imposed mirror symmetry (all atoms apart from one O atom lie on the mirror plane). In the crystal, anions and cations are linked by O—H...O and π–π stacking interactions [centroid–centroid distance = 3.4574 (6) Å], forming chains parallel to the b axis. Adjacent chains are further connected by N—H...O hydrogen bonds into a two-dimensional network.

Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10 kHz) and high performance in polarization switching up to 1 × 106 times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.

In the last several years, we have witnessed significant advances in molecular ferroelectrics, with the ferroelectric properties of molecular crystals approaching those of barium titanate. In addition, ferroelectricity has been observed in biological systems, filling an important missing link in bioelectric phenomena. In this perspective, we will present short historical notes on ferroelectrics, followed by an overview of the fundamentals of ferroelectricity. The latest developments in molecular ferroelectrics and biological ferroelectricity will then be highlighted, and their implications and potential applications will be discussed. We close by noting molecular ferroelectric as an exciting frontier between electronics and biology, and a number of challenges ahead are also described.