gent wearable medical devices (IWMDs) has advanced rapidly, with research emphasis on physiological/pathological factors inducing biosensing and active delivery of therapeutic agents in an ondemand manner. [1] IWMDs constitute a vast array of wearable types, such as wrist bands, smart contact lenses, smart patches, and electronic textiles, which are used to measure biophysical or biochemical signals and, most recently, to achieve therapeutic interference by establishing microenvironmental detection-delivery feedback cycles. Accordingly, IWMDs have become critical components in achieving personalized healthcare and precision medicine. [2] Such devices can provide predictive bio-analysis and offer timely treatment intervention, improving drug efficacy, overcoming the potential dangers due to delayed treatment, and expanding the flexibility of drug use in time and space.For biodetection and monitoring, wearable biosensing devices (WBDs) have been developed to detect many physiological features such as mechanical deformations, electrocardiogram (ECG) signals, body temperature, [3][4][5] and biochemical components such as glucose, calcium ions, and lactate. [6][7][8] For a long time, efforts have been made to advance WBDs by tracking single analytes to multiple analytes. Previous reviews have described several types of representative wearable sensors for healthcare monitoring. [9] For drug delivery, transdermal/topical wearable delivery devices (WDDs) are advantageous over oral and injection delivery modalities in terms of flexibility and scalability and have been utilized to deliver therapeutic agents such as polypeptides, [10][11][12] polysaccharides, [13] small molecules, [14] and growth factors [15] continuously and responsively. Recent studies indicate that wearable transdermal patches constructed from responsive materials show great advantages and attractive prospects in application of WDDs. [16] Despite the considerable development of WBDs and WDDs, efforts are being made to combine them into a single system to provide both sensing and delivery services, for which IWMDs are expected to realize two core functions: identification of physiological/pathological markers and delivery of therapeutic agents. [17] As Figure 1 shows, IWMDs are defined as composite pieces of equipment that contain multiple subsystems, including embedded sensors, drug repositories, and their connecting attachments. In addition, some other components, The primary roles of precision medicine are to perform real-time examination, administer on-demand medication, and apply instruments continuously. However, most current therapeutic systems implement these processes separately, leading to treatment interruption and limited recovery in patients. Personalized healthcare and smart medical treatment have greatly promoted research on and development of biosensing and drug-delivery integrated systems, with intelligent wearable medical devices (IWMDs) as typical systems, which have received increasing attention because of their non-invasive and custom...

Three-dimensional (3D) embedded printing is emerging as a potential solution for the fabrication of complex biological structures and with ultrasoft biomaterials. For the supporting medium, bulk gels can support a wide range of bioinks with higher printing resolution as well as better finishing surfaces than granular microgel baths. However, the difficulties of regulating the physical properties of existing bulk gel supporting baths limit the further development of this method. This work has developed a bulk gel supporting bath with easily regulable physical properties to facilitate soft-material fabrication. The proposed bath is composed based on the hydrophobic association between a hydrophobically modified hydroxypropylmethyl cellulose (H-HPMC) and Pluronic F-127 (PF-127). Its rheological properties can be easily regulated; in the preprinting stage by varying the relative concentration of components, during printing by changing the temperature, and postprinting by adding additives with strong hydrophobicity or hydrophilicity. This has made the supporting bath not only available for various bioinks with a range of printing windows but also easy to be removed. Also, the removal strategy is independent of printing conditions like temperature and ions, which empowers the bath to hold great potential for the embedded printing of commonly used biomaterials. The adjustable rheological properties of the bath were leveraged to characterize the embedded printing quantitatively, involving the disturbance during the printing, filament cross-sectional shape, printing resolution, continuity, and the coalescence between adjacent filaments. The match between the bioink and the bath was also explored. Furthermore, low-viscosity bioinks (with 0.008–2.4 Pa s viscosity) were patterned into various 3D complex delicate soft structures (with a 0.5–5 kPa compressive modulus). It is believed that such an easily regulable assembled bath could serve as an available tool to support the complex biological structure fabrication and open unique prospects for personalized medicine.

Embedded freeform writing addresses the contradiction between the material printability and biocompatibility for conventional extrusion-based bioprinting. However, the existing embedding mediums have limitations concerning the restricted printing temperature window, compatibility with bioinks or crosslinkers, and difficulties on medium removal. This work demonstrates a new embedding medium to meet the above demands, which composes of hydrophobically modified hydroxypropylmethyl cellulose (H-HPMC) and Pluronic F-127 (PF-127). The adjustable hydrophobic and hydrophilic associations between the components permit tunable thermoresponsive rheological properties, providing a programable printing window. These associations are hardly compromised by additives without strong hydrophilic groups, which means it is compatible with the majority of bioink choices. We use polyethylene glycol 400, a strong hydrophilic polymer, to facilitate easy medium removal. The proposed medium enables freeform writing of the millimetric complex tubular structures with great shape fidelity and cell viability. Moreover, five bioinks with up to five different crosslinking methods are patterned into arbitrary geometries in one single medium, demonstrating its potential in heterogeneous tissue regeneration. Utilizing the rheological properties of the medium, an enhanced adhesion writing method is developed to optimize the structure’s strand-to-strand adhesion. In summary, this versatile embedding medium provides excellent compatibility with multi-crosslinking methods and a tunable printing window, opening new opportunities for heterogeneous tissue regeneration.