Prediction of Fuhrman grade of renal clear cell carcinoma by multimodal MRI radiomics: a retrospective study

AIM

To explore the value of multimodal magnetic resonance imaging (MRI) radiomics combined with traditional radiologist-defined semantic characteristics and conventional (cMRI) and functional MRI (fMRI) texture features in predicting Fuhrman grade of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

The data of 89 patients with histopathologically proven ccRCC (low-grade, 54; high-grade, 35) were collected. Texture features were extracted from cMRI (T1- and T2-weighted imaging) and fMRI (Dixon-MRI; blood-oxygen-level dependent [BOLD]-MRI; and susceptibility-weighted imaging [SWI]) images, and the traditional characteristics (TC) were evaluated. Logistic regression analysis was performed to develop models based on TC, cMRI, and fMRI texture features for grading. Receiver operating characteristic (ROC) curve analysis and leave-group-out cross-validation (LGOCV) were performed to test the reliability of combined models.

RESULTS

Two T2-weighted imaging-based, two Dixon_W-based, one Dixon_F-based, one BOLD-based, and three SWI-based texture features, and three TC were extracted for feature selection. TC, cMRI, fMRI, cMRI+fMRI, cMRI+TC, fMRI+TC, and cMRI+fMRI+TC models were constructed. The AUC of the cMRI+fMRI+TC model for differentiating high- from low-grade ccRCC was 0.74, with 81.42% accuracy, 75.93% sensitivity, and 91.43% specificity. The fMRI+TC model exhibited a performance similar to that of the cMRI+fMRI+TC model (p>0.05). The areas under the curve (AUCs) of the fMRI+TC and cMRI+fMRI+TC models were significantly higher than those of the other five models (all p<0.05). For the cMRI+fMRI+TC model, the mean accuracy was 85.40% after 100 LGOCV for the test sets.

CONCLUSION

Multimodal MRI radiomics combined with TC, cMRI, and fMRI texture features may be a reliable quantitative approach for differentiating high-grade ccRCC from low-grade ccRCC.

An Antidehydration Hydrogel Based on Zwitterionic Oligomers for Bioelectronic Interfacing

Hydrogels are ideal interfacing materials for on-skin healthcare devices, yet their susceptibility to dehydration hinders their practical use. While incorporating hygroscopic metal salts can prevent dehydration and maintain ionic conductivity, concerns arise regarding metal toxicity due to the passage of small ions through the skin barrier. Herein, an antidehydration hydrogel enabled by the incorporation of zwitterionic oligomers into its network is reported. This hydrogel exhibits exceptional water retention properties, maintaining ≈88% of its weight at 40% relative humidity, 25 °C for 50 days and about 84% after being heated at 50 °C for 3 h. Crucially, the molecular weight design of the embedded oligomers prevents their penetration into the epidermis, as evidenced by experimental and molecular simulation results. The hydrogel allows stable signal acquisition in electrophysiological monitoring of humans and plants under low-humidity conditions. This research provides a promising strategy for the development of epidermis-safe and biocompatible antidehydration hydrogel interfaces for on-skin devices.

Contact Lens Sensor with Anti-jamming Capability and High Sensitivity for Intraocular Pressure Monitoring

Contact lens sensors provide a noninvasive approach for intraocular pressure (IOP) monitoring in patients with glaucoma. Accurate measurement of this imperceptible pressure variation requires highly sensitive sensors in the absence of simultaneously amplifying IOP signal and blinking-induced noise. However, current noise-reduction methods rely on external filter circuits, which thicken contact lenses and reduce signal quality. Here, we introduce a contact lens strain sensor with an anti-jamming ability by utilizing a self-lubricating layer to reduce the coefficient of friction (COF) to remove the interference from the tangential force. The sensor achieves exceptionally high sensitivity due to the strain concentration layout and the confined occurrence of sympatric microcracks. The animal tests prove our lens can accurately detect IOP safely and reliably.

Geometry-mediated bridging drives nonadhesive stripe wound healing

Wound healing through reepithelialization of gaps is of profound importance to the medical community. One critical mechanism identified by researchers for closing non-cell-adhesive gaps is the accumulation of actin cables around concave edges and the resulting purse-string constriction. However, the studies to date have not separated the gap-edge curvature effect from the gap size effect. Here, we fabricate micropatterned hydrogel substrates with long, straight, and wavy non-cell-adhesive stripes of different gap widths to investigate the stripe edge curvature and stripe width effects on the reepithelialization of Madin-Darby canine kidney (MDCK) cells. Our results show that MDCK cell reepithelization is closely regulated by the gap geometry and may occur through different pathways. In addition to purse-string contraction, we identify gap bridging either via cell protrusion or by lamellipodium extension as critical cellular and molecular mechanisms for wavy gap closure. Cell migration in the direction perpendicular to wound front, sufficiently small gap size to allow bridging, and sufficiently high negative curvature at cell bridges for actin cable constriction are necessary/sufficient conditions for gap closure. Our experiments demonstrate that straight stripes rarely induce cell migration perpendicular to wound front, but wavy stripes do; cell protrusion and lamellipodia extension can help establish bridges over gaps of about five times the cell size, but not significantly beyond. Such discoveries deepen our understanding of mechanobiology of cell responses to curvature and help guide development of biophysical strategies for tissue repair, plastic surgery, and better wound management.

Boosting the Piezoelectric Sensitivity of Amino Acid Crystals by Mechanical Annealing for the Engineering of Fully Degradable Force Sensors

Biodegradable piezoelectric force sensors can be used as implantable medical devices for monitoring physiological pressures of impaired organs or providing essential stimuli for drug delivery and tissue regeneration without the need of additional invasive removal surgery or battery power. However, traditional piezoelectric materials, such as inorganic ceramics and organic polymers, show unsatisfactory degradability, and cytotoxicity. Amino acid crystals are biocompatible and exhibit outstanding piezoelectric properties, but their small crystal size makes it difficult to align the crystals for practical applications. Here, a mechanical-annealing strategy is reported for engineering all-organic biodegradable piezoelectric force sensors using natural amino acid crystals as piezoelectric materials. It is shown that the piezoelectric constant of the mechanical-annealed crystals can reach 12 times that of the single crystal powders. Moreover, mechanical annealing results in flat and smooth surfaces, thus improving the contact of the crystal films with the electrodes and leading to high output voltages of the devices. The packaged force sensors can be used to monitor dynamic motions, including muscle contraction and lung respiration, in vivo for 4 weeks and then gradually degrade without causing obvious inflammation or systemic toxicity. This work provides a way to engineer all-organic and biodegradable force sensors for potential clinical applications.

Reprogramming Mitochondrial Metabolism in Synovial Macrophages of Early Osteoarthritis by a Camouflaged Meta-Defensome

Osteoarthritis (OA) is a low-grade inflammatory and progressive joint disease, and its progression is closely associated with an imbalance in M1/M2 synovial macrophages. Repolarizing pro-inflammatory M1 macrophages into the anti-inflammatory M2 phenotype is emerging as a strategy to alleviate OA progression but is compromised by unsatisfactory efficiency. In this study, the reprogramming of mitochondrial dysfunction is pioneered with a camouflaged meta-Defensome, which can transform M1 synovial macrophages into the M2 phenotype with a high efficiency of 82.3%. The meta-Defensome recognizes activated macrophages via receptor-ligand interactions and accumulates in the mitochondria through electrostatic attractions. These meta-Defensomes are macrophage-membrane-coated polymeric nanoparticles decorated with dual ligands and co-loaded with S-methylisothiourea and MnO₂ . Meta-Defensomes are demonstrated to successfully reprogram the mitochondrial metabolism of M1 macrophages by scavenging mitochondrial reactive oxygen species and inhibiting mitochondrial NO synthase, thereby increasing mitochondrial transcription factor A expression and restoring aerobic respiration. Furthermore, meta-Defensomes are intravenously injected into collagenase-induced osteoarthritis mice and effectively suppress synovial inflammation and progression of early OA, as evident from the Osteoarthritis Research Society International score. Therefore, reprogramming the mitochondrial metabolism can serve as a novel and practical approach to repolarize M1 synovial macrophages. The camouflaged meta-Defensomes are a promising therapeutic agent for impeding OA progression in tclinic.

Haptically Quantifying Young's Modulus of Soft Materials Using a Self-Locked Stretchable Strain Sensor

Simple and rapid Young's modulus measurements of soft materials adaptable to various scenarios are of general significance, and they require miniaturized measurement platforms with easy operation. Despite the advances made in portable and wearable approaches, acquiring and analyzing multiple or complicated signals necessitate tethered bulky components and careful preparation. Here, a new methodology based on a self-locked stretchable strain sensor to haptically quantify Young's modulus of soft materials (kPa-MPa) rapidly is reported. The method demonstrates a fingertip measurement platform, which endows a prosthetic finger with human-comparable haptic behaviors and skills on elasticity sensing without activity constraints. A universal strategy is offered toward ultraconvenient and high-efficient Young's modulus measurements with wide adaptability to various fields for unprecedented applications.

Pregnancy outcome after in-vitro fertilization/intracytoplasmic sperm injection in women with congenital uterus didelphys

OBJECTIVE

To investigate the pregnancy and obstetric outcomes of patients with congenital uterus didelphys who achieved clinical pregnancy after in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

METHODS

This was a retrospective matched-cohort study of 83 infertile patients with uterus didelphys who underwent IVF/ICSI and achieved clinical pregnancy from January 2005 to December 2018 at our center. For each patient in the study group, three control patients with normal uterine morphology who underwent IVF/ICSI in 2018 were selected randomly. Patients in the two groups were matched for number of gestational sacs, maternal age, infertility type, cause of infertility, fertilization method, endometrial thickness 1 day before embryo transfer and number of embryos transferred. The classification of congenital uterine anomalies was based on the American Fertility Society system (1988). The pregnancy and obstetric outcomes of the didelphic and control groups were compared separately for singleton and twin pregnancies, and for all pregnancies combined.

RESULTS

In singleton pregnancies, women with uterus didelphys had increased risk of preterm birth (odds ratio (OR), 4.68; rate difference (RD), 0.14; P < 0.001), Cesarean section (OR, 2.80; RD, 0.17; P = 0.016) and birth weight < 2500 g (OR, 4.06; RD, 0.10; P = 0.017) compared to women with normal uterine morphology. In twin pregnancies, the presence of uterus didelphys was associated with increased risk of preterm delivery (OR, 4.79; RD, 0.37; P = 0.006), perinatal mortality (OR, 3.16; RD, 0.19; P = 0.043) and birth weight < 2500 g (OR, 9.57; RD, 0.35; P = 0.001).

CONCLUSIONS

The presence of uterus didelphys was associated with significantly increased risk of some adverse pregnancy outcomes compared to pregnancies with normal uterine morphology in women who underwent IVF/ICSI. A twin pregnancy in women with uterus didelphys was associated with worse perinatal outcome. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Neutral particles pushed or pulled by laser pulses: erratum

We present an erratum to our Letter [Opt. Lett.41, 230 (2016)10.1364/OL.41.000230]. This erratum corrects three typing errors. The corrections have no influence on the results and conclusions of the original Letter.

Artificial Sense Technology: Emulating and Extending Biological Senses

Biological senses are critical for the survival of organisms. A great deal of attention has focused on elucidating the underlying physiological mechanisms of the senses, inspiring various sensing techniques. Despite progress in this area, gaps remain between the biological senses and conventional sensing techniques. In this Perspective, we propose the concept of artificial sense technology, which mimics the biological senses but differs in terms of objective sensing and intelligent feedback capabilities. We first summarize recent progress in the use of nanotechnologies to emulate the biological senses and then outline the advantages of artificial sense technology, which extend the capabilities of its biological counterparts. We envision artificial sense technology as a powerful perceptual interface that will play key roles in sensation substitution, digital healthcare, animal interactions, plant electronics, smart robots, and other areas that enrich the connections of the physical and virtual worlds.

Mechanomaterials: A Rational Deployment of Forces and Geometries in Programming Functional Materials

The knowledge of mechanics of materials has been extensively implemented in developing functional materials, giving rise to recent advances in soft actuators, flexible electronics, mechanical metamaterials, tunable mechanochromics, regenerative mechanomedicine, etc. While conventional mechanics of materials offers passive access to mechanical properties of materials in existing forms, a paradigm shift is emerging toward proactive programming of materials' functionality by leveraging the force-geometry-property relationships. Here, such a rising field is coined as "mechanomaterials". To profile the concept, the design principles in this field at four scales is first outlined, namely the atomic scale, the molecular scale, the manipulation of nanoscale materials, and the microscale design of structural materials. A variety of techniques have been recruited to deliver the multiscale programming of functional mechanomaterials, such as strain engineering, capillary assembly, topological interlocking, kirigami, origami, to name a few. Engineering optical and biological functionalities have also been achieved by implementing the fundamentals of mechanochemistry and mechanobiology. Nonetheless, the field of mechanomaterials is still in its infancy, with many open challenges and opportunities that need to be addressed. The authors hope this review can serve as a modest spur to attract more researchers to further advance this field.

The impact of maternal hypothyroidism on the prevalence of preeclampsia in a contemporary nationwide cohort

Introduction

Hypothyroidism is common with a prevalence of 3.7% in the general population and 3.1% in women of childbearing age (12–49) in the United State of America (USA) according to the National Health and Nutrition Examination Survey. Studies have found an increased prevalence of hypertension in patients with hypothyroidism. However, there is a dearth of literature exploring the association between hypothyroidism and hypertensive disorders in pregnancy, especially preeclampsia. Our study aims to fill that void.

Purpose

To examine the association between hypothyroidism and preeclampsia.

Methods

We conducted a retrospective cohort study using the latest available data from the USA National Inpatient Sample (2016). Using the ICD-10 codes, we identified patients admitted with a primary diagnosis of delivery and classified them into two cohorts based on the presence or absence of hypothyroidism. We compared the prevalence of preeclampsia and eclampsia among the patient with and without hypothyroidism. We used propensity score matching for age, hypertension, hyperlipidemia, obesity, anemia, hyperthyroidism, sleep apnea, chronic kidney disease, and smoking and repeated the analysis.

Results

We identified 752,054 patients who were admitted for delivery from January 1, 2016 to December 31, 2016. Of these, 726,769 did not have hypothyroidism and 25,285 had hypothyroidism. In the unmatched cohort, 1,572 patients had preeclampsia (6.2%, p&lt;0.001) in the hypothyroidism group and 32,539 (4.5%, p&lt;0.001) patients had preeclampsia in the non-hypothyroidism group. In the unmatched cohort, there was a significantly higher proportion of obesity (13.8% vs 8.2%, p&lt;0.001) and diabetes (3.3% vs 0.9%, p&lt;0.001) in the hypothyroidism group compared to the non hypothyroidism group. There were 25,282 patients in each group after propensity score matching. In the matched cohort, the prevalence of preeclampsia was still high in the hypothyroidism group compared to the non hypothyroidism group (6.2% vs 4.9, p&lt;0.001). The LOS was longer in the hypothyroidism group compared to the non hypothyroidism group (2.99±2.90 vs 2.75±2.42, p&lt;0.001). There was no statistical difference in the prevalence of eclampsia between the two groups (26 patients vs 30 patients, p=0.688). The difference in outcomes of death, cardiac arrest, acute kidney injury, acute respiratory failure and stroke were not statistically significant between these two groups.

Conclusion

Our study shows that hypothyroidism is associated with an increased prevalence of preeclampsia. The association existed even after propensity score matching for other common risk factors for preeclampsia. Given the retrospective nature of the study, we could not establish causation. Further prospective studies are required to find out if hypothyroidism leads to increased incidence of preeclampsia and if patients from hypothyroidism would benefit from prophylaxis for preeclampsia.

Funding Acknowledgement

Type of funding sources: None. Study design

1026 Assessing the Reliability of 3D Imaging for Wound Measurements

Aim

To investigate the inter and intra reliability of using 3D imaging to measure wounds.

Method

20 wound models of 4 different shaped wounds in 5 different colours were created from plastic mouldable beads. 3D images were taken using the BlasterX Senz3D camera and measured using the GPC Wound Measure application (version 3.15.0.0, UK). Intra-user reliability was determined comparing 20 wound measurements of each wound model. Inter-user reliability was determined by 5 different clinicians photographing each model and independently measuring each wound photo. The inter- and intra-rater measurements for wound surface area and volume were compared using the ICC and differences from the overall mean plotted on Bland-Altman graphs.

Results

The interclass co-efficient (ICC) for inter-rater reliability in measuring surface area was 0.958 (95% CI 0.919-0.981, p &lt; 0.005). The intra-rater reliability when measuring wound surface area was 0.996 (95% CI 0.993-0.998, p &lt; 0.005). For wound volume, the ICC for inter-rater reliability was 0.925 (95% CI 0.857-0.967, p &lt; 0.005) and 0.999 (95% CI 0.998-0.999, p &lt; 0.005) for intra-user reliability. 5.5% of measurements were outside 2 SD of the mean for wound volume.

Conclusions

3D imaging offers a quick, reliable, and easy to use solution to measuring wounds. We have shown it is a reliable and reproducible method of measuring wounds between different clinicians.

P–357 The risk factors for early pregnancy loss based on a logistic model following 13,977 infertile patients after in vitro fertilization

Study question

What are the risk factors for early pregnancy loss (EPL) after in vitro fertilization-embryo transfer (IVF-ET)?

Summary answer

The maternal age, gestational sac diameter, embryonic length, yolk sac diameter, heart rate of day 27–29 and endometrium thickness on transfer day were risk factors. What is known already: The first routine ultrasound scan is commonly arranged on day 27–29 after IVF-ET in most reproductive centers in China to determine the location and viability of the embryo. Individual maternal factors, such as a high maternal age (MA) and abnormal ultrasound parameters such as embryonic bradycardia and excessively large or small yolk sac diameter (YSD) have been shown to be associated with pregnancy failures. However, few studies focused on the risk factors of the IVF population, and little is known about the clinical meaning of ultrasound indicators of 27–29 days after transplantation.

Study design, size, duration

This was a retrospective study in a single reproductive centre. The infertile patients included in this study underwent IVF treatment between June 2016 to December 2017. Participants/materials, setting, methods: During this period, 13,977 women were identified with a singleton pregnancy by TVS at day 27–29 after IVF-ET. The gestational sac diameter (GSD), embryonic length (EL), embryonic heart rate (EHR) and YSD and the presence of intrauterine hematoma (IUH) were measured. The clinical characteristics were also collected. The first trimester pregnancy outcome of these women was noted at 12 weeks of gestation. A backward Wald logistic regression model was established to screen the risk factors.

Main results and the role of chance

1,926 cases of spontaneous miscarriage ≤12 weeks of gestation, which were assigned as EPL and 12,051 women with an ongoing pregnancy for &gt;12 weeks of gestation.

When compared with the ongoing pregnancy group, the MA, infertility duration and transfer cycle were significantly higher, and the day–14 human chorionic gonadotrophin and the endometrium (EM) thickness on transfer day were significantly lower in the EPL group (p &lt; 0.001). Based on the TVS measurements, the GSD (18.5±3.6 vs. 13.2±4.8 mm), EL (3.5±0.9 vs. 1.2±1.6 mm), YSD (3.6±0.4 vs. 2.6±1.5 mm) and EHR (114.5±12.2 vs. 42.4±53.5 bpm) were significantly greater in the ongoing pregnancy group than those in the EPL group (p &lt; 0.001). The incidence of IUH (16.0% vs. 18.8%, P = 0.002) was also markedly higher in the EPL group

MA, GSD, EL, YSD, EHR and EM on transfer day finally entered the logistic model after stepwise screening. The probability of EPL was: exp(z)/(1 + exp(z)), where z = 2.432 + (0.092 × MA) - (0.074 × EM) - (0.114 ×GSD) - (0.245 × EL) - (0.034 × HR) - (0.159 × YSD).

Limitations, reasons for caution

Data on smoking and clinical symptoms such as vaginal bleeding or abdominal pain were not included in the final analysis which might be possible risk factors. These predictors were derived from an IVF population, the situation may not be the same in the general population.

Wider implications of the findings: The risk factors for EPL after IVF-ET are clearly identified in this study. The logistic model which incorporates readily available data that are routinely collected in clinical practice could be used for calculating the risk of EPL and effectively guide subsequent medical plans.

Trial registration number

None

P–405 The diagnosis and management of heterotopic intramural pregnancy after in vitro fertilization-embryo transfer: six-case series

Study question

What are the ultrasonic characteristics of heterotopic intramural pregnancy (HIMP)? How to manage and what about the clinical outcomes of HIMP?

Summary answer

Expectant management may be a considerable choice for an non-viable intramural pregnancy (IMP). Most intrauteine pregnancies (IUPs) of HIMPs seems to have good outcomes.

What is known already

Heterotopic pregnancy (HP) post in vitro fertilization is very rare in infertility women, with a prevalence of 0.04%. HIMP is one of the rarest types of HP, where one gestational sac (GS) is embedded within the endometrial cavity and the other one GS is implanted in the myometriun. HIMP was firstly and only described by Jiangtao Lyu et al. in 2018. So far, little is known about its natural history and ultrasonic imaging characteristics. And there is no consensus regarding the ultrasound diagnosis and clinical management for HIMP due to few evidence-based medicine records.

Study design, size, duration

A retrospective observational study was conducted of 6 infertile women who obtained a HIMP through in vitro fertilization-embryo transfer (IVF-ET) between January 2009 and December 2019 at our reproductive centre.

Participants/materials, setting, methods

Six infertile women conceived a HIMP via IVF-ET were retrospectively retrieved between January 2009 and December 2019 at the Reproductive and Genetic Hospital of CITIC-Xiangya (Changsha City, China). The ultrasound diagnosis, clinical management and pregnancy outcome of these cases were analysed. The ultrasound findings, therapeutic methods and clinical outcomes were obtained from the hospital’s electronic medical records. This study was approved by the local ethics committee. Main results and the role of chance: Six women with HIMPs were retrospectively analysed. Among them, 5 cases were revealed by ultrasound scans; however, one case was misdiagnosed. The diagnostic accuracy was 83.3%.

Five cases of HIMP were diagnosed at initial scan. The diagnostic time ranged from 22 to 38 days after ET (5 + 6 - 7 + 6 weeks). Among them, an intramural GS was observed in all 5 cases; embryonic cardiac activity (ECA) was detected in one case by the followed-up scans; there was a yolk sac only in one case; an empty GS was noted in 3 cases. An IUP was revealed in all 6 cases, and ECA was observed in 5 cases at the initial diagnosis or later. A GS with a yolk sac only was showed in one case.

Among the 5 diagnostic women, one case with a live IMP was treated with laparoscopy at 8 + 1 weeks, 4 cases were managed expectantly. Of them, the IUPs of 4 cases delivered live infants and one case managed expectantly experienced miscarriage. In one case, IMP was misdiagnosed as interstitial pregnancy at day–28 scan. Exploratory laparoscopy and foetal reduction were performed at 8 + 2 weeks. Laparoscopy confirmed an IMP and the retained IUP delivered a live infant.

Limitations, reasons for caution

The case numbers are too few to draw any objective conclusions, because of the extreme rarity of HIMP. Thus, a further multi-centre larger prospective study will help to confidently illustrate the clinical significance, and effective and appropriate management method for women with a HIMP.

Wider implications of the findings: Our study showed that HIMP may not be as rare as previously reported. Increased awareness of this condition, better comprehension of the diagnostic criteria and improved resolution of ultrasound equipment may result in more frequent and accurate detection of HIMP, which will be helpful for early management to preserve IUP.

Trial registration number

Not applicable.

High dose insulin promotes the proliferation of vascular smooth muscle cells via AP-1/SM-α pathway

Proliferation of vascular smooth muscle cells (VSMCs) participates in multiple cardiovascular disorders, while the mechanism remains unclear. This study aims to investigate the effects of insulin on VSMC. Insulin was used to stimulate rat VSMCs, and the effects on cell cycle and proliferation were subsequently analyzed using flow cytometry. Furthermore, AP-1 and SM-α overexpression vectors were constructed and transfected into VSMCs. AP-1 and SM-α were inhibited by SR11302 and SM-α siRNA, respectively. The mRNA and protein expression levels were subsequently detected using the reversetranscription quantitative polymerase chain reaction and western blotting, respectively. AP-1 and SM-α gene promoter binding sites were determined using luciferase and chromatin immunoprecipitation assays. As a result, we found that high dose of insulin promoted proliferation of VSMCs and increased the percentage of cells in the S phase by downregulating AP-1. AP-1 was identified to bind to the SM-α gene promoter at locus 2-177 to upregulate SM-α gene expression. Inhibition of AP-1 led to the decrease of SM-α expression. Overexpression of SM-α directly suppressed proliferation of VSMCs, while knocking it down promoted the process. Therefore, this study revealed that insulin downregulated the expression of the SM-α gene by inhibiting AP-1, which in turn facilitated proliferation of VSMCs.

Spatiotemporal Oscillation in Confined Epithelial Motion upon Fluid-to-Solid Transition

Fluid-to-solid phase transition in multicellular assembly is crucial in many developmental biological processes, such as embryogenesis and morphogenesis. However, biomechanical studies in this area are limited, and little is known about factors governing the transition and how cell behaviors are regulated. Due to different stresses present, cells could behave distinctively depending on the nature of tissue. Here we report a fluid-to-solid transition in geometrically confined multicellular assemblies. Under circular confinement, Madin-Darby canine kidney (MDCK) monolayers undergo spatiotemporally oscillatory motions that are strongly dependent on the confinement size and distance from the periphery of the monolayers. Nanomechanical mapping reveals that epithelial tensional stress and traction forces on the substrate are both dependent on confinement size. The oscillation pattern and cellular nanomechanics profile appear well correlated with stress fiber assembly and cell polarization. These experimental observations imply that the confinement size-dependent surface tension regulates actin fiber assembly, cellular force generation, and cell polarization. Our analyses further suggest a characteristic confinement size (approximates to MDCK's natural correlation length) below which surface tension is sufficiently high and triggers a fluid-to-solid transition of the monolayers. Our findings may shed light on the geometrical and nanomechanical control of tissue morphogenesis and growth.

An artificial sensory neuron with visual-haptic fusion

Human behaviors are extremely sophisticated, relying on the adaptive, plastic and event-driven network of sensory neurons. Such neuronal system analyzes multiple sensory cues efficiently to establish accurate depiction of the environment. Here, we develop a bimodal artificial sensory neuron to implement the sensory fusion processes. Such a bimodal artificial sensory neuron collects optic and pressure information from the photodetector and pressure sensors respectively, transmits the bimodal information through an ionic cable, and integrates them into post-synaptic currents by a synaptic transistor. The sensory neuron can be excited in multiple levels by synchronizing the two sensory cues, which enables the manipulating of skeletal myotubes and a robotic hand. Furthermore, enhanced recognition capability achieved on fused visual/haptic cues is confirmed by simulation of a multi-transparency pattern recognition task. Our biomimetic design has the potential to advance technologies in cyborg and neuromorphic systems by endowing them with supramodal perceptual capabilities.

A Compliant Ionic Adhesive Electrode with Ultralow Bioelectronic Impedance

Simultaneous implementation of high signal-to-noise ratio (SNR) but low crosstalk is of great importance for weak surface electromyography (sEMG) signals when precisely driving a prosthesis to perform sophisticated activities. However, due to gaps with the curved skin during muscle contraction, many electrodes have poor compliance with skin and suffer from high bioelectrical impedance. This causes serious noise and error in the signals, especially the signals from low-level muscle contractions. Here, the design of a compliant electrode based on an adhesive hydrogel, alginate-polyacrylamide (Alg-PAAm) is reported, which eliminates those large gaps through the strong electrostatic interaction and abundant hydrogen bond with the skin. The obtained compliant electrode, having an ultralow bioelectrical impedance of ≈20 kΩ, can monitor even 2.1% maximal voluntary contraction (MVC) of muscle. Furthermore, benefiting from the high SNR of >5:1 at low-level MVC, the crosstalk from irrelevant muscle is minimized through reducing the electrode size. Finally, a prosthesis is successfully demonstrated to precisely grasp a needle based on a 9 mm² Alg-PAAm compliant electrode. The strategy to design such compliant electrodes provides the potential for improving the quality of dynamically weak sEMG signals to precisely control prosthesis in performing purposefully dexterous activity.

Devising Materials Manufacturing Toward Lab-to-Fab Translation of Flexible Electronics

Flexible electronics have witnessed exciting progress in academia over the past decade, but most of the research outcomes have yet to be translated into products or gain much market share. For mass production and commercialization, industrial adoption of newly developed functional materials and fabrication techniques is a prerequisite. However, due to the disparate features of academic laboratories and industrial plants, translating materials and manufacturing technologies from labs to fabs is notoriously difficult. Therefore, herein, key challenges in the materials manufacturing of flexible electronics are identified and discussed for its lab-to-fab translation, along the four stages in product manufacturing: design, materials supply, processing, and integration. Perspectives on industry-oriented strategies to overcome some of these obstacles are also proposed. Priorities for action are outlined, including standardization, iteration between basic and applied research, and adoption of smart manufacturing. With concerted efforts from academia and industry, flexible electronics will bring a bigger impact to society as promised.

Locally coupled electromechanical interfaces based on cytoadhesion-inspired hybrids to identify muscular excitation-contraction signatures

Coupling myoelectric and mechanical signals during voluntary muscle contraction is paramount in human-machine interactions. Spatiotemporal differences in the two signals intrinsically arise from the muscular excitation-contraction process; however, current methods fail to deliver local electromechanical coupling of the process. Here we present the locally coupled electromechanical interface based on a quadra-layered ionotronic hybrid (named as CoupOn) that mimics the transmembrane cytoadhesion architecture. CoupOn simultaneously monitors mechanical strains with a gauge factor of ~34 and surface electromyogram with a signal-to-noise ratio of 32.2 dB. The resolved excitation-contraction signatures of forearm flexor muscles can recognize flexions of different fingers, hand grips of varying strength, and nervous and metabolic muscle fatigue. The orthogonal correlation of hand grip strength with speed is further exploited to manipulate robotic hands for recapitulating corresponding gesture dynamics. It can be envisioned that such locally coupled electromechanical interfaces would endow cyber-human interactions with unprecedented robustness and dexterity.

Artificial Sensory Memory

Sensory memory, formed at the beginning while perceiving and interacting with the environment, is considered a primary source of intelligence. Transferring such biological concepts into electronic implementation aims at achieving perceptual intelligence, which would profoundly advance a broad spectrum of applications, such as prosthetics, robotics, and cyborg systems. Here, the recent developments in the design and fabrication of artificial sensory memory devices are summarized and their applications in recognition, manipulation, and learning are highlighted. The emergence of such devices benefits from recent progress in both bioinspired sensing and neuromorphic engineering technologies and derives from abundant inspiration and benchmarks from an improved understanding of biological sensory processing. Increasing attention to this area would offer unprecedented opportunities toward new hardware architecture of artificial intelligence, which could extend the capabilities of digital systems with emotional/psychological attributes. Pending challenges are also addressed to aspects such as integration level, energy efficiency, and functionality, which would undoubtedly shed light on the future development of translational implementations.

A supertough electro-tendon based on spider silk composites

Compared to transmission systems based on shafts and gears, tendon-driven systems offer a simpler and more dexterous way to transmit actuation force in robotic hands. However, current tendon fibers have low toughness and suffer from large friction, limiting the further development of tendon-driven robotic hands. Here, we report a super tough electro-tendon based on spider silk which has a toughness of 420 MJ/m3 and conductivity of 1,077 S/cm. The electro-tendon, mechanically toughened by single-wall carbon nanotubes (SWCNTs) and electrically enhanced by PEDOT:PSS, can withstand more than 40,000 bending-stretching cycles without changes in conductivity. Because the electro-tendon can simultaneously transmit signals and force from the sensing and actuating systems, we use it to replace the single functional tendon in humanoid robotic hand to perform grasping functions without additional wiring and circuit components. This material is expected to pave the way for the development of robots and various applications in advanced manufacturing and engineering.

Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.

[Research progress in imaging characteristics of precancerous nodules in hepatocellular carcinoma cells]

Hepatocarcinogenesis is a multi-step process in which detection of precancerous lesions and advanced hepatocellular carcinoma in its progressive stage is crucially important for predicting tumor behavior, estimating the extent of lesions, implementing the optimal treatment strategy, and improving the survival of patients. The rapid development and wide application of liver imaging technology, especially the application of hepatocyte-specific gadoxetate disodium MRI contrast agent (Gd-EOB-DTPA MRI), not only provide information on vascular changes of liver nodules and hepatocyte function, but also has become a precise diagnostic method for differentiating cirrhotic regenerative nodule (RN), low-grade dysplastic nodule (LGDN), high-grade dysplastic nodule (HGDN), early hepatocellular carcinoma and HCC. Hence, the risk for malignant progression is stratified. This review summarizes the value of Gd-EOB-DTPA MRI for early HCC diagnosis and analyzes the key concepts in the multi-step process of HCC development as well as the imaging manifestations of precancerous lesions that may eventually be transformed into typical HCC.

[Risk analysis for hypervascular transformation of precancerous lesion of hepatocellular carcinoma]

Objective: To investigate the risk factors for diagnosis of transformation of high-grade dysplastic nodules (HGDN) to hypervascular hepatocellular carcinoma (HCC) in patients with chronic liver disease with gadoxetate disodium-enhanced magnetic resonance imaging (MRI). Methods: 2 037 cases that underwent gadoxetate disodium-enhanced magnetic resonance imaging from January 2012 to December 2014 were retrospectively analyzed. 51 cases of HGDN with a background of chronic liver disease were screened and followed-up for at least 2 times with gadoxetate disodium-enhanced MRI scans and contrast enhanced CT scans was performed within 1 month before and after the first MRI. The endpoint of study was transformation of HGDN to hypervascular hepatocellular carcinoma, with a deadline of April 2019. Transformation was divided into transformed (group A) and untransformed (group B) group according to the presence or absence of hypervascularization. Linear regression was used to analyze the possible risk factors for hypervascular transformation. Results: There were 36 nodules in group A and 79 nodules in group B, and hypervascular transformation rate was 31.3% (36/115). On univariate analysis, the length and diameter of nodule was > 10.2 mm (P = 0.034), with annual growth rate > 2% (P < 0.001), and lipid content (P = 0.007) was related to the occurrence of hypervascularity. On multivariate analysis, the annual growth rate of nodules was an independent risk factor for the occurrence of hypervascularity (P < 0.000 1). Conclusion: The annual growth rate of HGDN in patients with chronic liver disease diagnosed with gadoxetate disodium-enhanced MRI imaging can be used as a potential predictor of hypervascularization.

Differential Homeostasis of Sessile and Pendant Epithelium Reconstituted in a 3D-Printed "GeminiChip"

Local mechanical cues can affect crucial fate decisions of living cells. Transepithelial stress has been discussed in the context of epithelial monolayers, but the lack of appropriate experimental systems leads current studies to approximate it simply as an in-plane stress. To evaluate possible contribution of force vectors acting in other directions, double epithelium in a 3D-printed "GeminiChip" containing a sessile and a pendant channel is reconstituted. Intriguingly, the sessile epithelia is prone to apoptotic cell extrusion upon crowding, whereas the pendant counterpart favors live cell delamination. Transcriptome analyses show upregulation of RhoA, BMP2, and hypoxia-signaling genes in the pendant epithelium, consistent with the onset of an epithelial-mesenchymal transition program. HepG2 microtumor spheroids also display differential spreading patterns in the sessile and pendant configuration. Using this multilayered GeminiChip, these results uncover a progressive yet critical role of perpendicular force vectors in collective cell behaviors and point at fundamental importance of these forces in the biology of cancer.

Broadband Extrinsic Self-Trapped Exciton Emission in Sn-Doped 2D Lead-Halide Perovskites

As emerging efficient emitters, metal-halide perovskites offer the intriguing potential to the low-cost light emitting devices. However, semiconductors generally suffer from severe luminescence quenching due to insufficient confinement of excitons (bound electron-hole pairs). Here, Sn-triggered extrinsic self-trapping of excitons in bulk 2D perovskite crystal, PEA₂ PbI₄ (PEA = phenylethylammonium), is reported, where exciton self-trapping never occurs in its pure state. By creating local potential wells, isoelectronic Sn dopants initiate the localization of excitons, which would further induce the large lattice deformation around the impurities to accommodate the self-trapped excitons. With such self-trapped states, the Sn-doped perovskites generate broadband red-to-near-infrared (NIR) emission at room temperature due to strong exciton-phonon coupling, with a remarkable quantum yield increase from 0.7% to 6.0% (8.6 folds), reaching 42.3% under a 100 mW cm^-2 excitation by extrapolation. The quantum yield enhancement stems from substantial higher thermal quench activation energy of self-trapped excitons than that of free excitons (120 vs 35 meV). It is further revealed that the fast exciton diffusion involves in the initial energy transfer step by transient absorption spectroscopy. This dopant-induced extrinsic exciton self-trapping approach paves the way for extending the spectral range of perovskite emitters, and may find emerging application in efficient supercontinuum sources.

Biomechano-Interactive Materials and Interfaces

The reciprocal mechanical interaction of engineered materials with biointerfaces have long been observed and exploited in biomedical applications. It contributes to the rise of biomechano-responsive materials and biomechano-stimulatory materials, constituting the biomechano-interactive interfaces. Here, endogenous and exogenous biomechanical stimuli available for mechanoresponsive interfaces are briefed and their mechanistic responses, including deformation and volume change, mechanomanipulation of physical and chemical bonds, dissociation of assemblies, and coupling with thermoresponsiveness are summarized. The mechanostimulatory materials, however, are capable of delivering mechanical cues, including stiffness, viscoelasticity, geometrical constraints, and mechanical loads, to modulate physiological and pathological behaviors of living tissues through the adaptive cellular mechanotransduction. The biomechano-interactive materials and interfaces are widely implemented in such fields as mechanotriggered therapeutics and diagnosis, adaptive biophysical sensors, biointegrated soft actuators, and mechanorobust tissue engineering, which have offered unprecedented opportunities for precision and personalized medicine. Pending challenges are also addressed to shed a light on future advances with respect to translational implementations.

Enhancing the Matrix Addressing of Flexible Sensory Arrays by a Highly Nonlinear Threshold Switch

The increasing need for smart systems in healthcare, wearable, and soft robotics is creating demand for low-power sensory circuits that can detect pressure, temperature, strain, and other local variables. Among the most critical requirements, the matrix circuitry to address the individual sensor device must be sensitive, immune to disturbances, and flexible within a high-density sensory array. Here, a strategy is reported to enhance the matrix addressing of a fully integrated flexible sensory array with an improvement of 108 fold in the maximum readout value of impedance by a bidirectional threshold switch. The threshold switch shows high flexibility (bendable to a radius of about 1 mm) and a high nonlinearity of ≈1010 by using a nanocontact structure strategy, which is revealed and validated by molecular dynamics simulations and experiments at variable mechanical stress. Such a flexible electronic switch enables a new generation of large-scale flexible and stretchable electronic and optoelectronic systems.

Combinatorial Nano-Bio Interfaces

Nano-bio interfaces are emerging from the convergence of engineered nanomaterials and biological entities. Despite rapid growth, clinical translation of biomedical nanomaterials is heavily compromised by the lack of comprehensive understanding of biophysicochemical interactions at nano-bio interfaces. In the past decade, a few investigations have adopted a combinatorial approach toward decoding nano-bio interfaces. Combinatorial nano-bio interfaces comprise the design of nanocombinatorial libraries and high-throughput bioevaluation. In this Perspective, we address challenges in combinatorial nano-bio interfaces and call for multiparametric nanocombinatorics (composition, morphology, mechanics, surface chemistry), multiscale bioevaluation (biomolecules, organelles, cells, tissues/organs), and the recruitment of computational modeling and artificial intelligence. Leveraging combinatorial nano-bio interfaces will shed light on precision nanomedicine and its potential applications.

Plasticizing Silk Protein for On-Skin Stretchable Electrodes

Soft and stretchable electronic devices are important in wearable and implantable applications because of the high skin conformability. Due to the natural biocompatibility and biodegradability, silk protein is one of the ideal platforms for wearable electronic devices. However, the realization of skin-conformable electronic devices based on silk has been limited by the mechanical mismatch with skin, and the difficulty in integrating stretchable electronics. Here, silk protein is used as the substrate for soft and stretchable on-skin electronics. The original high Young's modulus (5-12 GPa) and low stretchability (<20%) are tuned into 0.1-2 MPa and > 400%, respectively. This plasticization is realized by the addition of CaCl₂ and ambient hydration, whose mechanism is further investigated by molecular dynamics simulations. Moreover, highly stretchable (>100%) electrodes are obtained by the thin-film metallization and the formation of wrinkled structures after ambient hydration. Finally, the plasticized silk electrodes, with the high electrical performance and skin conformability, achieve on-skin electrophysiological recording comparable to that by commercial gel electrodes. The proposed skin-conformable electronics based on biomaterials will pave the way for the harmonized integration of electronics into human.

Mediating Short-Term Plasticity in an Artificial Memristive Synapse by the Orientation of Silica Mesopores

Memristive synapses based on resistive switching are promising electronic devices that emulate the synaptic plasticity in neural systems. Short-term plasticity (STP), reflecting a temporal strengthening of the synaptic connection, allows artificial synapses to perform critical computational functions, such as fast response and information filtering. To mediate this fundamental property in memristive electronic devices, the regulation of the dynamic resistive change is necessary for an artificial synapse. Here, it is demonstrated that the orientation of mesopores in the dielectric silica layer can be used to modulate the STP of an artificial memristive synapse. The dielectric silica layer with vertical mesopores can facilitate the formation of a conductive pathway, which underlies a lower set voltage (≈1.0 V) compared to these with parallel mesopores (≈1.2 V) and dense amorphous silica (≈2.0 V). Also, the artificial memristive synapses with vertical mesopores exhibit the fastest current increase by successive voltage pulses. Finally, oriented silica mesopores are designed for varying the relaxation time of memory, and thus the successful mediation of STP is achieved. The implementation of mesoporous orientation provides a new perspective for engineering artificial synapses with multilevel learning and forgetting capability, which is essential for neuromorphic computing.

Mechano-Based Transductive Sensing for Wearable Healthcare

Wearable healthcare presents exciting opportunities for continuous, real-time, and noninvasive monitoring of health status. Even though electrochemical and optical sensing have already made great advances, there is still an urgent demand for alternative signal transformation in terms of miniaturization, wearability, conformability, and stretchability. Mechano-based transductive sensing, referred to the efficient transformation of biosignals into measureable mechanical signals, is claimed to exhibit the aforementioned desirable properties, and ultrasensitivity. In this Concept, a focus on pressure, strain, deflection, and swelling transductive principles based on micro-/nanostructures for wearable healthcare is presented. Special attention is paid to biophysical sensors based on pressure/strain, and biochemical sensors based on microfluidic pressure, microcantilever, and photonic crystals. There are still many challenges to be confronted in terms of sample collection, miniaturization, and wireless data readout. With continuing efforts toward solving those problems, it is anticipated that mechano-based transduction will provide an accessible route for multimode wearable healthcare systems integrated with physical, electrophysiological, and biochemical sensors.

Synergistic Lysosomal Activatable Polymeric Nanoprobe Encapsulating pH Sensitive Imidazole Derivative for Tumor Diagnosis

Developing optical tumor imaging probes with minimal background noise is very important for its early detection of small lesions and accurate diagnosis of cancer. To overcome the bottleneck of low signal to noise ratio and sensitivity, it needs further improvement in fluorescent probe design and understanding of tumor development process. Recent reports reveal that lysosome's acidity in cancer cells can be below 4.5 with high Na⁺ /H⁺ exchange activity, which makes it an ideal target intracellular organelle for cancer diagnosis based on the variation of pH. Herein, a boron 2-(2'-pyridyl) imidazole complex derivative (BOPIM-N) is developed, with the ability to show a pH-activatable "OFF-ON" fluorescent switch by inhibiting twisted intramolecular charge transfer upon protonation at pH 3.8-4.5, which is studied for its selective viable cancer cell imaging ability in both in vitro and in vivo experiments. Interestingly, BOPIM-N can specifically emit green fluorescence in lysosomes of cancer cells, indicating its promising cancer cell specific imaging ability. More importantly, nanoformulated BOPIM-N probes can be specifically light-ON in tumor bearing site of nude mice with resolution up to cellular level, indicating its potential application in tumor diagnosis and precision medicine.

Nanomechanical Force Mapping of Restricted Cell-To-Cell Collisions Oscillating between Contraction and Relaxation

Contact-mediated cell migration strongly determines the invasiveness of the corresponding cells, collective migration, and morphogenesis. The quantitative study of cellular response upon contact relies on cell-to-cell collision, which rarely occurs in conventional cell culture. Herein, we developed a strategy to activate a robust cell-to-cell collision within smooth muscle cell pairs. Nanomechanical traction force mapping reveals that the collision process is promoted by the oscillatory modulations between contraction and relaxation and orientated by the filopodial bridge composed of nanosized contractile machinery. This strategy can enhance the occurrence of cell-to-cell collision, which renders it advantageous over traditional methods that utilize micropatterned coating to confine cell pairs. Furthermore, modulation of the balance between cell tugging force and traction force can determine the repolarization of cells and thus the direction of cell migration. Overall, our approach could help to reveal the mechanistic contribution in cell motility and provide insights in tissue engineering.

Orientational Coupling Locally Orchestrates a Cell Migration Pattern for Re-Epithelialization

Re-epithelialization by collective migration of epithelial cells over a heterogeneous environment to restore tissue integrity and functions is critical for development and regeneration. Here, it is reported that the spatial organization of adjacent adherent paths within sparsely distributed extracellular matrix (ECM) has a significant impact on the orientational coupling between cell polarization and collective cell migration. This coupling effect determines the migration pattern for human keratinocytes to regain their cohesion, which impacts the occupancy of epithelial bridge and the migration velocity in wound repair. Statistical studies suggest the converging organization of ECM, in which adjacent paths become closer to each other and finally converge to a junctional point, facilitating collective cell migration mostly within variable ECM organization, as the polarization of the advancing cell sheet is remodeled to align along the direction of cell migration. The findings may help to design implantable ECM to optimize efficient skin regeneration.

Nanomechanically Visualizing Drug-Cell Interaction at the Early Stage of Chemotherapy

A detailed understanding of chemotherapy is determined by the response of cell to the formation of the drug-target complex and its corresponding sudden or eventual cell death. However, visualization of this early but important process, encompassing the fast dynamics as well as complex network of molecular pathways, remains challenging. Herein, we report that the nanomechanical traction force is sensitive enough to reflect the early cellular response upon the addition of chemotherapeutical molecules in a real-time and noninvasive manner, due to interactions between chemotherapeutic drug and its cytoskeleton targets. This strategy has outperformed the traditional cell viability, cell cycle, cell impendence as well as intracellular protein analyses, in terms of fast response. Furthermore, by using the nanomechanical traction force as a nanoscale biophysical marker, we discover a cellular nanomechanical change upon drug treatment in a fast and sensitive manner. Overall, this approach could help to reveal the hidden mechanistic steps in chemotherapy and provide useful insights in drug screening.

Programmable Nano-Bio Interfaces for Functional Biointegrated Devices

A large amount of evidence has demonstrated the revolutionary role of nanosystems in the screening and shielding of biological systems. The explosive development of interfacing bioentities with programmable nanomaterials has conveyed the intriguing concept of nano-bio interfaces. Here, recent advances in functional biointegrated devices through the precise programming of nano-bio interactions are outlined, especially with regard to the rational assembly of constituent nanomaterials on multiple dimension scales (e.g., nanoparticles, nanowires, layered nanomaterials, and 3D-architectured nanomaterials), in order to leverage their respective intrinsic merits for different functions. Emerging nanotechnological strategies at nano-bio interfaces are also highlighted, such as multimodal diagnosis or "theragnostics", synergistic and sequential therapeutics delivery, and stretchable and flexible nanoelectronic devices, and their implementation into a broad range of biointegrated devices (e.g., implantable, minimally invasive, and wearable devices). When utilized as functional modules of biointegrated devices, these programmable nano-bio interfaces will open up a new chapter for precision nanomedicine.

Osteoinduction of Calcium Phosphate Ceramics in Four Kinds of Animals for 1 Year: Dog, Rabbit, Rat, and Mouse

INTRODUCTION

Bone grafts are in great demand. Synthetic materials have been extensively studied as substitutes for autografts. Calcium phosphate ceramics are promising synthetic bone replacement materials. Because they share chemical similarities with human bone mineral, they show excellent biocompatibility and osteoinductivity.

OBJECTIVE

Calcium phosphate ceramics have been used to fill bone defects in preclinical study in a variety of animals. This study aimed to investigate the osteogenesis ability of calcium phosphate ceramics in 4 kinds of animals.

METHODS

Φ3 × 5 mm hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) cylinders were implanted into the dorsal muscle of rats and mice, whereas Φ5 × 10 mm cylinders were implanted into the dorsal muscle of dogs and rabbits. One year after implantation, the ceramics were harvested to perform hematoxylin and eosin (HE) staining and Masson-trichrome staining. The new bone tissues were observed and the area percentage of new bone was compared in the 4 kinds of animals.

RESULTS

A large number of new bone and bone marrow tissues were observed in dogs, rabbits, and mice, but not in rats; and the area percentage of new bone in mice was significantly higher than that in dogs and rabbits (P < .05). Calcium phosphate ceramics have good biocompability and biological safety, and the degree of ease of osteogenesis was as follows: mouse > dog > rabbit > rat.

CONCLUSION

To achieve better effects for bone transplantation, mouse should be chosen as the preferred experimental model based on these advantages: economic, convenience, and osteogenesis ability.