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Biosensors and chemical sensors for healthcare applications are garnering interest due to their potential to provide continuous and real-time physiological information, chemical information, and noninvasive measurements of biochemical markers in human biofluids, such as tears, saliva, sweat, interstitial fluid, and human volatiles. Recent developments have focused on electrochemical biosensors and monitoring of metabolites, proteins, chemicals, and bacteria. The measurement of biophysical quantities of the human body has been studied in healthcare and medicine. Many flexible, wearable, and detachable sensors have been developed and commercialized to monitor relevant parameters in sports, healthcare, and medicine. Here, we introduce many challenges regarding the integration of sensors and biosensors into the monitoring of biological and chemical information for the internet of things (IoT) in healthcare. IoT sensors are set to improve quality of life (QoL) and living standards.

recently attracted considerable research attention thanks to its low mass density (2.33 g cm −3 ), nontoxicity, and biocompatibility. [6,7] Besides, the intrinsic semiconductor and tunable on-chip characteristics enable Si to be a central platform of several applications, including optoelectronics, [8,9] microelectronics, [10] smart sensors, [11,12] solar cells, [13][14][15] and drug-delivery systems. [16] From an energy perspective, seamless integration of energy storage systems onto these Si-based functional devices is highly desirable toward portable and wearable applications, or when the power supply is intermittent. Therefore, significant research has focused on Sibased energy storage, including Si-based batteries (mainly Li-ion batteries) and Sibased supercapacitors.In Li-ion batteries, Si has been intensively studied as a promising anode candidate due to the low working potential of 0.4 V (vs Li + /Li) and high theoretical capacity (3579 mAh g −1 ), compared to the conventional graphite anode. [17] However, as an alloy-type material, Si anode notoriously suffers from huge volume expansion/shrinkage during lithiation/delithiation (over 300%), leading to severe delamination and pulverization of electrodes, together with unstable and nonuniform solid electrolyte interphase layers. [18] These characteristics considerably affect the cyclic stability of Si-anode Li-ion batteries. Several strategies have been implemented to address the aforementioned challenges, including composite and coating materials design, [19][20][21][22][23][24] binder design, [25][26][27][28] and electrolyte modification. [29][30][31][32] These approaches nevertheless are mainly based on wet-chemistry methods with complicated synthesis techniques, which are not suitable for an integrated system. A very thin layer of Si has been proven to accommodate the mechanical stress during alloying/ dealloying. [33][34][35] Inspired by this concept, several studies have focused on thin film Si-anode batteries based on integrated circuit (IC)-compatible routes, and their potentials to be integrated with other functional Si-based devices. [36][37][38][39] However, the intricate charge storage mechanism of Si-based batteries inevitably limits their applications. In particular, batteries suffer from low power performance. Although parallel and/or series connections of batteries can guarantee high power, the device volume will be increased, which is not desirable for an integrated system. Furthermore, owing to their inferior stability and lifetime, batteries unavoidably require frequent replacements, meaning that they cannot be applied in devices such as bioimplant chips, biosensors, and harsh-environment sensors. [40,41] Silicon (Si), as the second most abundant element on Earth, has been a central platform of modern electronics owing to its low mass density and unique semiconductor properties. From an energy perspective, all-in-one integration of power supply systems onto Si-based functional devices is highly desirable, which inspires significant study ...

In this paper, we propose a fabrication and characterization of silicon mold for PMMA hot embossing process. Silicon molds were fabricated from silicon wafer with thickness of 500µm. First, DRIE technique was performed after optimized etching time and deposition (passivation) time to obtain a depth of 30µm with positive tapered sidewall of 1°. This is very important for de-molding process while hot embossing. Second, in order to reduce scalloping steps on the sidewall after DRIE, silicon molds were soaked in the TMAH solution 20% at 80°C for 10 minutes without magnetic stirrer. Third, to further reduce the friction coefficient between sidewall surface and PMMA substrate while de-molding, the post-passivation technique was applied to create a thin layer of Teflon-like material on the surface of the sidewall of silicon mold. These smooth silicon molds were used to emboss several models of PMMA patterns and comb-drive actuators, as well as applications in Micro Conveyer System. The PMMA patterns obtained after hot embossing process had very sharp edge and aspect ratio of 15 with minimum feature sized of 2µm.