Silk-protein-based gradient hydrogels with multimode reprogrammable shape changes for biointegrated devices.

Biocompatible and morphable hydrogels capable of multimode reprogrammable, and adaptive shape changes are potentially useful for diverse biomedical applications. However, existing morphable systems often rely on complicated structural designs involving cumbersome and energy-intensive fabrication processes. Here, we report a simple electric-field-activated protein network migration strategy to reversibly program silk-protein hydrogels with controllable and reprogrammable complex shape transformations. The application of a low electric field enables the convergence of net negatively charged protein cross-linking networks toward the anode (isoelectric point plane) due to the pH gradient generated in the process, facilitating the formation of a gradient network structure and systems suitable for three-dimensional shape change. These tunable protein networks can be reprogrammed or permanently fixed by control of the polymorphic transitions. We show that these morphing hydrogels are capable of conformally interfacing with biological tissues by programming the shape changes and a bimorph structure consisting of aligned carbon nanotube multilayers and the silk hydrogels was assembled to illustrate utility as an implantable bioelectronic device for localized low-voltage electrical stimulation of the sciatic nerve in a rabbit.

Dynamic Shape Change of Liquid Crystal Polymer Based on An Order-Order Phase Transition.

Liquid crystal actuators conventionally undergo shape changes across an order-disorder phase transition between liquid crystal (LC) and isotropic phases. In this study, we introduce an innovative Liquid Crystal Polymer (LCP) actuator harnessing an order-order LC phase transition mechanism. The LCP film is easily stretchable within the LC phase, facilitated by the π-π stacking of phenyl groups serving as robust physical crosslinking points, and thereby transforms to a stable monodomain structure. The resultant monodomain LCP actuator shows a distinctive reversible dynamic shape change, exhibiting extension followed by contraction along the LC director on cooling. The extension is propelled by the reversible smectic C to smectic A phase transition, and the contraction is attributed to the re-entry to the smectic C phase from smectic A phase. Thermal annealing temperature determines this peculiar dynamic shape change, which occurs during both heating and cooling processes. This pivotal attribute finds manifestation in gripper and flower-shaped actuators, adeptly executing grabbing and releasing as well as blooming and closure motions within a single thermal stimulation. In essence, our study introduces an innovative approach to the realm of LCP actuators, ushering in a new avenue for the design and fabrication of versatile and dynamically responsive LCP actuators.

Joining Two Switches in One Nano-Object: Photoacidity and Photoisomerization in Electrostatic Self-Assembly.

Multi-switchable supramolecular nano-objects that respond to irradiation of different wavelengths with changes in size and shape have been built from two different water-soluble molecular switches, joined by attachment to the same polyelectrolyte. Accordingly, two wavelength-specific reactions, namely the excited-state proton dissociation of a photoacid and the cis-trans isomerization of an azo dye, are combined in one supramolecular nano-object that is stable in aqueous solution. The concept has potential in the fields of sensors, molecular motors, and transport.

Pressure-Based Soft Agents.

Biological agents have bodies that are composed mostly of soft tissue. Researchers have resorted to soft bodies to investigate Artificial Life (ALife)-related questions; similarly, a new era of soft-bodied robots has just begun. Nevertheless, because of their infinite degrees of freedom, soft bodies pose unique challenges in terms of simulation, control, and optimization. Herein I propose a novel soft-bodied agents formalism, namely, pressure-based soft agents (PSAs): spring-mass membranes containing a pressurized medium. Pressure endows the agents with structure, while springs and masses simulate softness and allow the agents to assume a large gamut of shapes. PSAs actuate both locally, by changing the resting lengths of springs, and globally, by modulating global pressure. I optimize the controller of PSAs for a locomotion task on hilly terrain, an escape task from a cage, and an object manipulation task. The results suggest that PSAs are indeed effective at the tasks, especially those requiring a shape change. I envision PSAs as playing a role in modeling soft-bodied agents, such as soft robots and biological cells.

Evaluating stored platelet shape change using imaging flow cytometry.

Platelets are routinely stored at room temperature for 5-7 days before transfusion. Stored platelet quality is traditionally assessed by Kunicki's morphology score. This method requires extensive training, experience, and is highly subjective. Moreover, the number of laboratories familiar with this technique is decreasing. Cold storage of platelets has recently regained interest because of potential advantages such as reduced bacterial growth and preserved function. However, platelets exposed to cold temperatures change uniformly from a discoid to a spherical shape, reducing the morphology score outcomes to spheroid versus discoid during cooling. We developed a simpler, unbiased screening tool to measure temperature-induced platelet shape change using imaging flow cytometry. When reduced to two dimensions, spheres appear circular, while discs are detected on a spectrum from fusiform to circular. We defined circular events as having a transverse axis of >0.8 of the longitudinal axis and fusiform events ≤0.8 of the longitudinal axis. Using this assay, mouse and human platelets show a temperature and time-dependent, two-dimensional shape change from fusiform to circular, consistent with their three-dimensional change from discs to spheres. The method we describe here is a valuable tool for detecting shape change differences in response to agonists or temperature and will help screening for therapeutic measures to mitigate the cold-induced storage lesion.

What is the context? Platelets for transfusion are currently stored for 5­7 days at room temperature, increasing the risk for bacterial growthCold storage reduces the risk for bacterial growth but reduces circulation timeStored platelet quality can be assessed by the light microscopy-based Morphology Score, first described in the 1970sDownsides of the Morphology Score include subjectivity, extensive training, and reduced availability in platelet laboratories.What is new? In this study, we provide data showing that the Morphology score is reduced to a binary spheres versus discs response in cold-exposed plateletsWe developed an imaging flow cytometry-based approach to quantify platelets' response to cold based on the two-dimensional projection of the three-dimensional shapes, i.e., fusiform (discoid) versus circular (discoid and spherical)We provide validation of this approach in mouse and human plateletsWhat is the impact?This study provides an easy and unbiased tool for laboratories working on circumventing the cold-induced storage lesion or documenting spherical shape change in general.

Zinc Electrode Cycling in Deep Eutectic Solvent Electrolytes: An Electrochemical Study.

Among post-lithium ion battery technologies, rechargeable chemistries with Zn anodes bear notable technological promise owing to their high theoretical energy density, lower manufacturing cost, availability of raw materials and inherent safety. However, Zn anodes, when employed in aqueous electrolytes, suffer from hydrogen evolution, passivation, and shape changes. Alternative electrolytes can help tackle these issues, preserving the green and safe characteristics of aqueous-based ones. Deep eutectic solvents (DESs) are promising green and low-cost non-aqueous solvents for battery electrolytes. Specifically, the cycling of Zn anodes in DESs is expected to be reversible, chiefly owing to their dendrite-suppression capability. Nevertheless, apart from a few studies on Zn plating, insight into the cathodic-anodic electrochemistry of Zn in DESs is still very limited. In view of developing DES-based battery electrolytes, it is crucial to consider that a potential drawback might be their low ionic conductivity. Water molecules can be added to the eutectic mixtures by up to 40% to increase the diffusion coefficient of the electroactive species and lower the electrolyte viscosity without destroying the eutectic nature. In this study, we address the electrochemistry of Zn in two different hydrated DESs (ChU and ChEG with ~30% H2O). Fundamental electrokinetic and electrocrystallization studies based on cyclic voltammetry and chronoamperometry at different cathodic substrates are completed with a galvanostatic cycling test of Zn|Zn symmetric CR2032 coin cells, SEM imaging of electrodes and in situ SERS spectroscopy. This investigation concludes with the proposal of a specific DES/H2O/ZnSO4-based electrolyte that exhibits optimal functional performance, rationalized on the basis of fundamental electrochemical data, morphology evaluation and modeling of the cycling response.

Preparation and shape change of silver nanoparticles (AgNPs) loaded on the dialdehyde cellulose by in-situ synthesis method.

With the improvement of medical and health care level in our society, the demand for antibacterial materials is increasing. In this work, we prepared the antibacterial materials by loading silver nanoparticles (AgNPs) on the dialdehyde cellulose (DAC) with in-situ synthesis method. DAC was prepared by pretreating cellulose fiber with sodium metaperiodate (NaIO4) to convert the hydroxyl group into aldehyde group, and then reacted with silver nitrate (AgNO3) to obtain AgNPs loaded on DAC. UV-Vis results show that the characteristic absorption peak of AgNPs at 428 nm appeared in the AgNPs-loaded-DAC. It was observed by SEM that the spherical AgNPs were distributed uniformly on the DAC surface without obvious flocculation. The color of DAC was not changed significantly, indicating that a small amount of AgNPs was loaded. In addition, sodium citrate (Na3C6H5O7) was added in the reaction of DAC and AgNO3 and its effect on the formation of AgNPs was studied. The results demonstrated that the color of DAC turned deeper and finally dark yellow with reaction time extended. When the reaction time was 60 h, the spherical AgNPs were gradually grown and transformed into triangular prism on the DAC surface. The antibacterial properties of AgNPs showed inhibition zones of 4.90 mm and 7.35 mm (60 h) against Gram-negative (E. coli) and Gram-positive (S. aureus), respectively, which increased by 40.00% and 14.85% compared with spherical AgNPs (2.5 h) obtained without Na3C6H5O7. The research of AgNPs-loaded cellulose-based materials promotes the development prospect of new nano-antibacterial materials. Supplementary Information: The online version contains supplementary material available at 10.1007/s10570-022-04692-6.

Platelet Hemostasis Reactions at Different Temperatures Correlate with Intracellular Calcium Concentration.

Hypo- and hyperthermia affect both primary and secondary hemostasis; however, there are controversial data concerning platelet activation and the underlying mechanisms under hypo- and hyperthermia. The discrepancies in the data could be partly explained by different approaches to hemostatic reactions analysis. We applied a new LaSca-TMF laser particle analyzer for a simultaneous fluorescence and laser scattering analysis of platelet responses at different temperatures. Human platelets were activated by ADP in a wide range of temperatures, and platelet transformations (e.g., a shape change reaction, aggregation and clot formation) and the intracellular calcium concentration ([Ca2+]i) were analyzed by LaSca-TMF and confocal microscopy. The platelet shape change reaction gradually increased with a rising temperature. The platelet aggregation strongly decreased at low ADP concentrations with the augmentation of the temperature and was independent of the temperature at high ADP concentrations. In contrast, the clotting time decreased with a temperature increase. Similar to the aggregation response, a rise in [Ca2+]i triggered by low ADP concentrations was higher under hypothermic conditions and the differences were independent of the temperature at high ADP concentrations. We showed that the key reactions of cellular hemostasis are differentially regulated by temperature and demonstrated for the first time that an accelerated aggregation under hypothermic conditions directly correlated with an increased level in [Ca2+]i in platelets.

Porous Liquid-Crystalline Networks with Hydrogel-Like Actuation and Reconfigurable Function.

A porous liquid-crystalline network (LCN), prepared by using a template method, was found to exhibit peculiar actuation functions. The creation of porosity makes the initially hydrophobic LCN behave like a hydrogel, capable of absorbing a large volume of water (up to ten times the sample size of LCN). When the amount of absorbed water is relatively small (about 100 % swelling ratio), the porous LCN displays anisotropic swelling in water and, in the same time, the retained uniaxial alignment of mesogens ensures a thermally induced shape change associated with a LC-isotropic phase transition. Combining the characteristic actuation mechanisms of LCN (order-disorder transition of mesogens) and hydrogel (water absorption), such porous LCNs can be explored for versatile stimuli-triggered shape transformations. Moreover, the porosity enables loading/removal/reloading of functional fillers such as ionic liquids, photothermal dyes and fluorophores, which imparts the porous LCN actuator with reconfigurable functions such as ionic conductivity, light-driven locomotion, and emissive color.

Prostaglandin D2 metabolites activate asthmatic patient-derived type 2 innate lymphoid cells and eosinophils via the DP2 receptor.

BACKGROUND: Prostaglandin D2 (PGD2) signaling via prostaglandin D2 receptor 2 (DP2) contributes to atopic and non-atopic asthma. Inhibiting DP2 has shown therapeutic benefit in certain subsets of asthma patients, improving eosinophilic airway inflammation. PGD2 metabolites prolong the inflammatory response in asthmatic patients via DP2 signaling. The role of PGD2 metabolites on eosinophil and ILC2 activity is not fully understood. METHODS: Eosinophils and ILC2s were isolated from peripheral blood of atopic asthmatic patients. Eosinophil shape change, ILC2 migration and IL-5/IL-13 cytokine secretion were measured after stimulation with seven PGD2 metabolites in presence or absence of the selective DP2 antagonist fevipiprant. RESULTS: Selected metabolites induced eosinophil shape change with similar nanomolar potencies except for 9α,11ß-PGF2. Maximal values in forward scatter of eosinophils were comparable between metabolites. ILC2s migrated dose-dependently in the presence of selected metabolites except for 9α,11ß-PGF2 with EC50 values ranging from 17.4 to 91.7 nM. Compared to PGD2, the absolute cell migration was enhanced in the presence of Δ12-PGD2, 15-deoxy-Δ12,14-PGD2, PGJ2, Δ12-PGJ2 and 15-deoxy-Δ12,14-PGJ2. ILC2 cytokine production was dose dependent as well but with an average sixfold reduced potency compared to cell migration (IL-5 range 108.1 to 526.9 nM, IL-13 range: 125.2 to 788.3 nM). Compared to PGD2, the absolute cytokine secretion was reduced in the presence of most metabolites. Fevipiprant dose-dependently inhibited eosinophil shape change, ILC2 migration and ILC2 cytokine secretion with (sub)-nanomolar potencies. CONCLUSION: Prostaglandin D2 metabolites initiate ILC2 migration and IL-5 and IL-13 cytokine secretion in a DP2 dependent manner. Our data indicate that metabolites may be important for in vivo eosinophil activation and ILC2 migration and to a lesser extent for ILC2 cytokine secretion.

Passive skeletal muscle can function as an osmotic engine.

Muscles are composite structures. The protein filaments responsible for force production are bundled within fluid-filled cells, and these cells are wrapped in ordered sleeves of fibrous collagen. Recent models suggest that the mechanical interaction between the intracellular fluid and extracellular collagen is essential to force production in passive skeletal muscle, allowing the material stiffness of extracellular collagen to contribute to passive muscle force at physiologically relevant muscle lengths. Such models lead to the prediction, tested here, that expansion of the fluid compartment within muscles should drive forceful muscle shortening, resulting in the production of mechanical work unassociated with contractile activity. We tested this prediction by experimentally increasing the fluid volumes of isolated bullfrog semimembranosus muscles via osmotically hypotonic bathing solutions. Over time, passive muscles bathed in hypotonic solution widened by 16.44 ± 3.66% (mean ± s.d.) as they took on fluid. Concurrently, muscles shortened by 2.13 ± 0.75% along their line of action, displacing a force-regulated servomotor and doing measurable mechanical work. This behaviour contradicts the expectation for an isotropic biological tissue that would lengthen when internally pressurized, suggesting a functional mechanism analogous to that of engineered pneumatic actuators and highlighting the significance of three-dimensional force transmission in skeletal muscle.

Pyk2 downstream of G12/13 pathways regulates platelet shape change through RhoA/p160ROCK.

Rho/Rho-kinase downstream of G12/13 plays an important role in the regulation of calcium-independent platelet shape change. We have previously shown that proline-rich tyrosine kinase 2 (Pyk2) is activated downstream of G12/13 pathways. In this study, we evaluated the role of Pyk2 in G12/13-induced platelet shape change. We used low concentrations of YFLLRNP, a heptapeptide binding to protease-activated receptor 1 (PAR1), or PAR4-activating peptide AYPGKF in the presence of Gαq inhibitor YM254890 to selectively stimulate G12/13 pathways. We found that G12/13-induced platelet shape change was completely inhibited in the presence of Pyk2 inhibitors AG17 and TAT-Pyk2-CT, suggesting an important role of Pyk2 in platelet shape change. In addition, AYPGKF-induced shape change in Gq -/- platelets was completely inhibited in the presence of AG17 or RhoA/p160ROCK inhibitor Y27632, confirming the role of Pyk2 in RhoA-dependent shape change. Furthermore, AYPGKF-induced platelet aggregation and dense granule secretion were inhibited by blocking Pyk2 or RhoA. Finally, G12/13-induced myosin phosphatase target subunit 1 (MYPT1) phosphorylation was inhibited by AG17, confirming that Pyk2 regulates RhoA/p160ROCK activation in platelets. These results demonstrate that Pyk2 downstream of G12/13 pathways regulates platelet shape change as well as platelet aggregation and dense granule secretion through the regulation of RhoA/p160ROCK.

Multicomponent DNA Polymerization Motor Gels.

Hydrogels with the ability to change shape in response to biochemical stimuli are important for biosensing, smart medicine, drug delivery, and soft robotics. Here, a family of multicomponent DNA polymerization motor gels with different polymer backbones is created, including acrylamide-co-bis-acrylamide (Am-BIS), poly(ethylene glycol) diacrylate (PEGDA), and gelatin-methacryloyl (GelMA) that swell extensively in response to specific DNA sequences. A common mechanism, a polymerization motor that induces swelling is driven by a cascade of DNA hairpin insertions into hydrogel crosslinks. These multicomponent hydrogels can be photopatterned into distinct shapes, have a broad range of mechanical properties, including tunable shear moduli between 297 and 3888 Pa and enhanced biocompatibility. Human cells adhere to the GelMA-DNA gels and remain viable during ≈70% volumetric swelling of the gel scaffold induced by DNA sequences. The results demonstrate the generality of sequential DNA hairpin insertion as a mechanism for inducing shape change in multicomponent hydrogels, suggesting widespread applicability of polymerization motor gels in biomaterials science and engineering.

Arsenic induces platelet shape change through altering focal adhesion kinase-mediated actin dynamics, contributing to increased platelet reactivity.

Arsenic, an environmental contaminant in drinking water worldwide is well-established to increase cardiovascular diseases (CVDs) in humans. Of these, thrombotic events represent a major adverse effect associated with arsenic exposure, for which an abundance of epidemiological evidence exists. Platelet aggregation constitutes a pivotal step in thrombosis but arsenic alone doesn't induce aggregation and the mechanism underlying arsenic-induced thrombosis still remains unclear. Here we demonstrated that arsenic induces morphological changes of platelets, i.e., contraction and pseudopod projection, the primal events of platelet activation, which can increase platelet reactivity. Arsenite induced prominent platelet shape changes in a dose-dependent manner in freshly isolated human platelets. Of note, arsenite suppressed focal adhesion kinase (FAK) activity, which in turn activated RhoA, leading to altered actin assembly through LIMK activation, and subsequent cofilin inactivation. Arsenic-induced platelet shape change appeared to increase the sensitivity to thrombin and ADP-induced aggregation. Supporting this, latrunculin A, an inhibitor of actin-dynamics abolished it. Taken together, we demonstrated that arsenic induces cytoskeletal changes and shape changes of platelets through FAK-mediated alteration of actin dynamics, which renders platelets reactive to activating stimuli, ultimately contributing to increased thrombosis.

A Novel Side-Chain Liquid Crystal Elastomer Exhibiting Anomalous Reversible Shape Change.

Liquid crystalline elastomers (LCEs) have been actively investigated as stimuli-controlled actuators and soft robots. The basis of these applications is the ability of LCEs to undergo a reversible shape change upon a liquid crystalline (LC)-isotropic phase transition. Herein, we report the synthesis of a novel LCE based on a side-chain liquid crystalline polymer (SCLCP). In contrast to known LCEs, this LCE exhibits a striking anomalous shape change. Subjecting a mechanically stretched monodomain strip to LC-disorder phase transition, both the length and width of the strip contract in isotropic phase, and both elongate in LC phase. This thermally induced behaviour is the result of a subtle interplay between the relaxation of polymer main chain oriented along the stretching direction and the disordering of side-group mesogens oriented perpendicularly to the stretching direction. This finding points out potential design of LCEs of this peculiar type and possible applications to exploit.

Threshold of the upper airway cross-section for hypopnea onset during sleep and its identification under waking condition.

BACKGROUND: There is currently no method that can predict whether or under what condition hypopnea, even obstructive sleep apnea (OSA), will occur during sleep for individuals based on credible parameters measured under waking condition. We propose a threshold concept based on the narrowest cross-sectional area of the upper airway (CSA-UA) and aim to prove our hypothesis on the threshold of the area for hypopnea onset (TAHO), which can be used as an indicator of hypopnea onset during sleep and measured while awake. METHODS: We performed magnetic resonance imaging for 20 OSA patients to observe CSA-UA changes during fluid accumulation in the neck caused by elevating their legs, and identified TAHO by capturing the sudden enlargement in CSA-UA. Correlation analyses between TAHO and the body mass index (BMI), and between the reduction in CSA-UA and the increase in the neck circumference (NC) with fluid accumulation were performed. Logistic regression analysis was performed for identifying OSA patients based on the behaviors of their CSA-UA changes during leg raising. Shape changes of airway cross-section were also investigated. RESULTS: Four CSA-UA change patterns after fluid redistribution were identified. Six patients had similar CSA-UA variation behaviors observed in healthy subjects. From the other three change patterns involving 14 patients, a threshold value of CSA-UA 0.63 ± 0.21 cm2 was identified for normal breathing. Data showed a positive correlation between TAHO and BMI (r = 0.681, p = 0.0007), and a negative correlation between the reduction in CSA-UA and the increase in NC (r = - 0.513, p = 0.051) with fluid accumulation. A sigmoid function for the probability of being a OSA patient p = 1/[1 + exp. (4.836 + 3.850 t-8.4 h)] was obtained to effectively separate OSA patients from normal subjects. The upper airway narrowing occurred in anteroposterior, lateral, or both directions, suggesting different tendencies of upper airway collapse in patients. Three types of shape changes in the cross-section of the upper airway, which had different effects on airway resistance, were measured. CONCLUSIONS: Our findings prove TAHO hypothesis. The threshold measured while awake for normal breathing can be used clinically as the indicator of hypopnea onset during sleep, and therefore to identify OSA patients under waking condition and design effective personalized treatments for OSA patients. Both shape and size changes in the cross-section of the upper airway affect airway resistance significantly. Shape change in the cross-section of the upper airway can provide key clinical information on the collapse patterns of the upper airway for individuals.

Defective rapid cell shape and transendothelial migration by calpain-1 null neutrophils.

It has been proposed that Ca2+ activation of calpain-1 is an important trigger for rapid cell spreading by neutrophils. In this paper, we have investigated this by assessing the ex vivo functioning of neutrophils from calpain-1 null mice, Calpain-1 null neutrophils failed to migrate through TNF-activated endothelial monolayers. The failure to transmigrate through endothelial monolayers was therefore unlikely to be due to a failure of chemotaxis as chemotaxis by adherent calpain-1 null neutrophils towards fMLP was unpaired. In contrast, the capacity of calpian-1 neutrophils to spontaneously spread was limited to smaller diameters than for wild type cells. Photolytic uncaging of IP3 with Individual wild type neutrophils resulted in a large Ca2+ signal and rapid cell spreading. In contrast, calpain-1 neutrophils failed to spread in response to the IP3-induced Ca2+ signal. This work has therefore demonstrated that the presence of calpain-1 was required for effective rapid cell spreading by neutrophils.

Multitemperature Responsive Self-Folding Soft Biomimetic Structures.

Untethered, millimeter-scale, stimuli-responsive shape change structures are critical to the function of autonomous devices, smart materials, and soft robotics. Temperature in a range compatible with physiological or ambient environmental conditions is an excellent cue to trigger actuation of soft structures for practical biomimetic applications. Previously, a range of thermally responsive self-folding soft structures has been described and utilized in a variety of applications from tissue engineering to minimally invasive surgery. In order to extend these concepts to more complex devices, thermally responsive bilayer structures composed of poly[oligo (ethylene glycol) methyl ether methacrylate] (POEGMA) gels that swell at three different temperatures are described. The lower critical solution temperature and volume transition temperature of POEGMA are tuned by varying the side chain length and the extent of copolymerization. The swelling properties of the POEGMA gels are characterized and a multilayer photopatterning process is described that is used to create soft biomimetic structures that change shape in a sequential manner while displaying multistate behaviors.

Localization Microscopy of Actin Cytoskeleton in Human Platelets.

Here, we measure the actin cytoskeleton arrangement of different morphological states of human platelets using a new protocol for photo-switching of rhodamine class fluorophores. A new medium composition was established for imaging the cytoskeleton using Alexa Fluor 488 conjugated to phalloidin. Morphological states of platelets bound to a glass substrate are visualized and quantified by two-dimensional localization microscopy at nanoscopic resolution. Marker-less drift correction yields localization of individual Alexa 488 conjugated to phalloidin with a positional accuracy of 12 nm.

Anisotropic Shape Changes of Silica Nanoparticles Induced in Liquid with Scanning Transmission Electron Microscopy.

Liquid-phase transmission electron microscopy (TEM) is used for in-situ imaging of nanoscale processes taking place in liquid, such as the evolution of nanoparticles during synthesis or structural changes of nanomaterials in liquid environment. Here, it is shown that the focused electron beam of scanning TEM (STEM) brings about the dissolution of silica nanoparticles in water by a gradual reduction of their sizes, and that silica redeposites at the sides of the nanoparticles in the scanning direction of the electron beam, such that elongated nanoparticles are formed. Nanoparticles with an elongation in a different direction are obtained simply by changing the scan direction. Material is expelled from the center of the nanoparticles at higher electron dose, leading to the formation of doughnut-shaped objects. Nanoparticles assembled in an aggregate gradually fuse, and the electron beam exposed section of the aggregate reduces in size and is elongated. Under TEM conditions with a stationary electron beam, the nanoparticles dissolve but do not elongate. The observed phenomena are important to consider when conducting liquid-phase STEM experiments on silica-based materials and may find future application for controlled anisotropic manipulation of the size and the shape of nanoparticles in liquid.