Photonic Crystal Hydrogel Research Articles

A multifunctional and tough lotus root starch-based bio-photonic hydrogel for stretchable fabric pattern color change and water rewriting.

Photonic crystal hydrogels (PCHs) are innovative materials that translate imperceptible deformations and humidity changes into visible colors, broadening the applications of photonics in bioengineering and smart materials. To overcome poor mechanical properties of traditional PCHs limited by weak intermolecular forces, we designed a PCH with a dual-network framework comprising N-isopropylacrylamide-co-acrylamide (NIPAM-co-AM) and biomass lotus root starch (LR). Since LR is rich in hydroxyl groups, it can undergo molecular linkage entanglement with the NIPAM-co-AM hydrogel matrix, forming hydrogen bonds that significantly enhance the mechanical properties of the PCH. We have prepared PCH films capable of conveying multidimensional information about the extent and distribution of transient deformation by encapsulating magnetic photonic crystal microspheres (MPCMs) within a hydrogel matrix. The PCH films were found to have ultrafast response time (< 10 s), full-color tunable range, high spatial resolution, excellent mechanical toughness (tensile up to 0.17 MPa) and sensitivity (2.52 nm %-1), and were able to sense relative humidity (RH) from 11 % to 98 %. Equipped with a dynamically reconfigurable lattice, this dual-responsive (tensile/humidity) PCH not only facilitates the creation of water-rewritable photonic films but also holds promise for integration into structural color elastic fabrics, thereby presenting novel prospects for smart textile applications.

Smart photonic crystal hydrogels for visual glucose monitoring in diabetic wound healing

Diabetes is a global chronic disease that seriously endangers human health and characterized by abnormally high blood glucose levels in the body. Diabetic wounds are common complications which associate with impaired healing process. Biomarkers monitoring of diabetic wounds is of great importance in the diabetes management. However, actual monitoring of biomarkers still largely relies on the complex process and additional sophisticated analytical instruments. In this work, we prepared hydrogels composed of different modules, which were designed to monitor different physiological indicators in diabetic wounds, including glucose levels, pH, and temperature. Glucose monitoring was achieved based on the combination of photonic crystal (PC) structure and glucose-responsive hydrogels. The obtained photonic crystal hydrogels (PCHs) allowed visual monitoring of glucose levels in physiological ranges by readout of intuitive structural color changes of PCHs during glucose-induced swelling and shrinkage. Interestingly, the glucose response of double network PCHs was completed in 15 min, which was twice as fast as single network PCHs, due to the higher volume fraction of glucose-responsive motifs. Moreover, pH sensing was achieved by incorporation of acid-base indicator dyes into hydrogels; and temperature monitoring was obtained by integration of thermochromic powders in hydrogels. These hydrogel modules effectively monitored the physiological levels and dynamic changes of three physiological biomarkers, both in vitro and in vivo during diabetic wound healing process. The multifunctional hydrogels with visual monitoring of biomarkers have great potential in wound-related monitoring and treatment.Graphical abstract

Two-dimensional photonic crystal acetylcholinesterase hydrogel and organohydrogel sensors for efficient detection of organophosphorus compounds

Sensors capable of detecting organophosphorus (OP) compounds have attracted the most attention owing to severe OP contamination worldwide. Despite many years of research, the developed OP sensors mainly focused on detecting water-soluble OPs in proper environments and the exploration of OP sensors suitable in resource-limited areas is extremely challenging. Here, a simple two-dimensional photonic crystal (2D PC) hydrogel featuring capabilities of effectively quantitative determination of OP compounds is facilely constructed by immobilizing the enzyme acetylcholinesterase (AChE) onto a bovine serum albumin (BSA) protein hydrogel. Owing to the specific interaction between AChE and OP compounds, the OP compounds are easily bound to the hydrogel, triggering volume phase transition and resulting in apparent Debye diffraction ring variations. The resulting hydrogel sensors show a limit of detection (LoD) of 2.23 nM for trichlorfon and 0.07 nM for diethyl methylphosphonate (DMPP), respectively. On the basis of the hydrogel, a responsive organohydrogel is facilely fabricated utilizing a solvent exchange strategy to meet the requirements of applications in harsh environments and detection of the non-water-soluble OP compounds. The organohydrogel sensors, however, demonstrated a LoD of 0.70 μM for trichlorfon and 4.46 μM for DMPP, respectively. This work provides new light on the development of next-generation stable, low-cost, and portable field sensing devices.

Wearable photonic crystal double network hydrogel sensor based on structural color analysis

Abstract This paper introduces a high-toughness photonic crystal (PhCs) dual-network hydrogel sensor designed for mechanical sensing, which enables quantitative analysis of structural color using the HSB color space. The hydrogel achieves a maximum tensile strain of 250% under a tensile stress of 3.5 MPa, thanks to its dual-network structure comprising a covalently cross-linked polyacrylamide (PAM) network and an ionically cross-linked sodium alginate (SA) network. At an 80% tensile strain, the PAM-SA photonic crystal hydrogel displays a blue shift in the bandgap wavelength of over 130 nm and demonstrates a sensitivity of 1.69 nm/%. The analysis of the force-induced color change in the PAM-SA photonic crystal hydrogel utilized both RGB and HSB color spaces. In the HSB color space, the hue component (H) exhibited a strong linear correlation with strain (R2&gt;0.95), indicating the feasibility of quantitative structural color analysis using HSB. As a wearable sensor, the PAM-SA photonic crystal hydrogel precisely detects human motion via bandgap displacement (R2=0.989) and structural color change (R2=0.978). The PAM-SA PhCs hydrogel, featuring easily accessible color information and high sensitivity, has broad potential applications in wearable devices and mechanical sensors.

Highly sensitive colorimetric detection of ascorbic acid using molecularly imprinted photonic crystal hydrogel sensor

Molecular imprinted photonic crystal hydrogel (MICPH) sensors have gained recognition as an efficient platform for selectively detecting analyte molecules. In the present work, we report the development and implementation of a colorimetric sensor based on MIPCH for the selective detection of Ascorbic acid (AA). The fabrication process of the MIPCH sensor involves the photo-polymerization of a hydrogel precursor solution containing AA molecules, which is encapsulated in the interstitial spaces of photonic crystal (PC) opal film. Following the encapsulation, these molecules are selectively removed from the hydrogel network, forming an AA-MIPCH sensor. The sensor exhibits a vivid structural color that redshifts upon rebinding with different concentrations of AA molecules. This alteration in structural coloration serves as a straightforward and visually discernible indicator of the sensor response and enables the quantitative measurement of the target molecule. The sensor exhibits remarkable sensitivity, featuring a low limit of detection (LoD) of 0.011 µM with high selectivity, minimal response time, and promising long-term stability. In addition, the sensor demonstrates its capability to detect the AA even from the complex matrix. A CNN-based deep learning algorithm in MATLAB® was employed to quantitatively predict the concentration of the target molecule. The integration with the machine learning algorithm yields a highly efficient and accurate smart sensor system that is well-suited for real-time sensing of ascorbic acid.

Thermochromic structural color based on pressure storage-release toward emerging applications

Conventional thermochromic photonic crystal (TPC) hydrogels and liquids have gained prominence due to their unique capability of adjusting their colors by temperature (T). However, challenges including non-recordable structural colors, poor stability, and limited color tunability significantly limit their advanced applications. To address these issues, a versatile pressure-stored TPC (PSTPC) with repeatable fixable compressed non-close-packing structures has been fabricated based on combining phase-changing materials and elastic photonic crystals. Distinguishing from conventional TPCs, PSTPCs possess 1) recordable colors with excellent stability under normal conditions; 2) adjustable colors from red to blue by simply altering storable pressure; and 3) a T-triggered color change by releasing the pressure. These PSTPCs have been experimentally proved to be ideal candidates for various applications, including hot warning labels, ink-free rewritable papers, and elaborate anti-counterfeiting tags. This work offers a new perspective for designing and fabricating combined materials-based stimulus-responsive structural color materials with advanced multifunctional applications.

A smart photonic crystal hydrogel sensor based on 18-crown-6/Ba2+ host–guest interactions for highly selective and visual Ba2+ detection

Barium ions (Ba2+) contamination is a serious environmental problem worldwide. The currently existing Ba2+-detection techniques are generally expensive, time-consuming, and complicated. Therefore, the development of a simple, inexpensive, rapid, and effective strategy to detect Ba2+ in water is of great importance. Herein, we first report a smart photonic crystal hydrogel (PCH) sensor for simple, highly selective, and naked-eye detection of Ba2+ in water based on 18-crown-6/Ba2+ host–guest interactions. This sensor was composed of a poly(benzo-18-crown-6-acrylamide-co-N-isopropylacrylamide-co-acrylamide) (PBCNA) intelligent hydrogel with embedding Fe3O4@SiO2 colloidal photonic crystals (CPCs). The prepared PBCNA PCH sensor demonstrated pH and temperature-dependent Ba2+-detection performances. Besides, the Ba2+-responded PCH sensor could be easily regenerated via simple washing using hot/cold water at least 20 times without compromising its detection performance. Such a PCH sensor with obvious advantages of portability, ease of operation, cost-effectiveness, high selectivity and excellent regenerability, provides a simple and effective strategy to monitor Ba2+ in contaminated water.

Dual-network photonic crystal hydrogels with mechanochromic property and enhanced water retention for multi-responsive applications

Photonic crystal hydrogels are obtained by assembling Fe3O4@C nanoparticles within the agar/P(N-isopropylacrylamide-acrylamide) (agar/P(NIPAm-Am)) dual-networks. The dual-network photonic crystal hydrogel offers a combination of structural color, mechanochromic behavior, water retention, solvent identification features, making it an exciting prospect for applications such as chromogenic display and sensing.

Dual-Mode Multicolor Display Based on Structural and Fluorescent Color CdS Photonic Crystal Hydrogel.

In this study, we prepared a multicolor structural-fluorescent CdS-PEGDA photonic crystal hydrogel (SFC-CPH) with a dual display mode, which has two different optical states: structural color mode and fluorescent color mode. SFC-CPH displays structural color mode under visible light and fluorescent color mode under ultraviolet light. Initially, monodisperse CdS colloidal particles were synthesized via a hydrothermal method, leading to the self-assembly of a photonic crystal template. The high refractive index of CdS contributes to the photonic crystals' low-angle dependence and vivid structural colors. Then, a variety of fluorescent molecules were doped into poly(ethylene glycol) diacrylate (PEGDA) hydrogel and combined with photonic crystals with distinct structural colors to prepare three distinct colors of SFC-CPH. We also investigated the optical characteristics and surface properties of these photonic crystal hydrogels. Based on these dual-mode display characteristics, we designed several dual-mode display patterns and a method for information encoding. The unique property of this photonic crystal hydrogel material suggests its substantial potential for applications in information storage, security, and encoding, offering innovative avenues in the realm of information display.

Agarose-Based Hydrogel Film with Embedded Oriented Photonic Nanochains for Sensing pH.

Responsive photonic crystal hydrogel sensors are renowned for their colorimetric sensing ability and can be utilized in many fields such as medical diagnosis, environmental detection, food safety, and industrial production. Previously, our group invented responsive photonic nanochains (RPNCs), which improve the response speed of photonic crystal hydrogel sensors by at least 2 to 3 orders of magnitude. However, RPNCs are dispersed in a liquid medium, which needs a magnetic field to orient them for the generation of structural colors. In addition, during repeated use, the process of cleaning and redispersing can cause entanglement, breakage, and a loss of RPNCs, resulting in poor stability. Moreover, when mixing with the samples in liquid, the RPNCs may lead to the contamination of the samples being tested. In this paper, we incorporate one-dimensional oriented RPNCs with agarose gel film to prepare heterogeneous hydrogel films. Thanks to the non-responsive and porous nature of the agarose gel, the protons diffuse freely in the gel, which facilitates the fast response of the RPNCs. Furthermore, the "frozen" RPNCs in agarose gel not only enable the display of structural colors without the need for a magnet but also improve the cycling stability and long-term durability of the sensor, and will not contaminate the samples. This work paves the way for the application of photonic crystal sensors.

A novel photonic crystal hydrogel inverse opal fluorescence enhancement platform for highly sensitive immunoassay of tumor markers

Cancer is a significant global health issue, necessitating early detection for effective diagnosis and treatment. We presented a novel method for detecting tumor markers using fluorescence-enhanced photonic crystal hydrogel inverse opal (PC-GELIO) membranes. We efficiently fabricated large-area, low-crack photonic crystal membranes using a homemade microfluidic chip. Composed of PEG-DA and PEG, the hydrogel replicated the photonic crystal structure, yielding photonic crystal hydrogel inverse opal membranes with a unique photonic band gap and inverse opal porous structure. These properties afford the PC-GELIO platform several advantages: Firstly, the high stability of the internal nanostructure in the large-area, low-crack photonic crystals film, prepared using the homemade microfluidic chip, is crucial for preserving the platform's exceptional fluorescence-enhanced sensing capabilities. Secondly, the peak wavelength emitted by fluorescent molecules aligns with the photonic band gap (PBG), significantly enhancing the fluorescence signal through the low-photon effect. Lastly, the high specific surface area provides numerous binding targets for biomolecule modification, and the hydrogel offers a uniform liquid environment conducive to biomolecule binding. We evaluated the fluorescence-enhanced sensing performance of the platform using alpha-fetoprotein (AFP). The limit of quantification (LOQ) for AFP was determined to be as low as 23 pg/mL, representing an order of magnitude improvement compared to non-enhanced platforms (0.29 ng/mL and 0.25 ng/mL). Consequently, this novel fluorescence-enhanced photonic crystal hydrogel inverse opal platform holds significant potential as a straightforward and efficient method for biomolecular detection.

Rapid Fabrication of Large-Grain Opal Films and Photonic Crystal Hydrogel Sensors by a Filter Paper-Enhanced Evaporation Chip.

Developing a rapid fabrication method for crack-free opal films is a significant challenge with broad applications. We developed a microfluidic platform known as the "filter paper-enhanced evaporation microfluidic chip" (FPEE-chip) for the fabrication of photonic crystal and inverse opal hydrogel (IOPH) films. The chip featured a thin channel formed by bonding double-sided adhesive poly(ethylene terephthalate) with a polymethyl methacrylate cover and a glass substrate. This channel was then filled with nanosphere colloids. The water was guided to evaporate rapidly at the surface of the filter paper, allowing the nanospheres to self-assemble and accumulate within the channel under capillary forces. Experimental results confirmed that the self-assembly method based on the FPEE-chip was a rapid platform for producing high-quality opal, with centimeter-sized opal films achievable in less than an hour. Furthermore, the filter paper altered the stress release mechanism of the opal films during drying, resulting in fewer cracks. This platform was proven capable of producing large-grain, crack-free opal films of up to 30 mm2 in size. We also fabricated crack-free IOPH pH sensors that exhibited color and size responsiveness to pH changes. The coefficient of variation of the gray color distribution for crack-free IOPH ranged from 0.03 to 0.07, which was lower than that of cracked IOPH (ranging from 0.07 to 0.14). Additionally, the grayscale peak value in 1 mm2 of the crack-free IOPH was more than twice that of the cracked IOPH at the same pH. The FPEE-chip demonstrated potential as a candidate for developing vision sensors.

Smartphone‐Based Molecularly Imprinted Photonic Crystal Hydrogel Sensor for the Label‐Free Detection of Bisphenol A

AbstractHere, the implementation of a smartphone‐based portable molecularly imprinted photonic crystal hydrogel (MIPCH) colorimetric sensor for the visual and label‐free detection of bisphenol A (BPA) in water samples is reported. The sensor is prepared by photopolymerizing BPA‐added hydrogel precursor solution within the voids of a photonic crystal opal film, followed by the extraction of BPA molecules. Rebinding of the BPA analyte to the MIPCH causes the hydrogel to swell, leading to a significant redshift in the diffracting spectrum. The MIPCH sensor exhibits a low limit of detection of 0.96 × 10−15 m. The sensor also shows linear response in the femtomolar range, rapid responsiveness (≤6 min), selective detection of BPA in complex matrices, long‐term stability, and reproducibility. Images of the sensor responses are used to train a deep‐learning‐based regression model on a smartphone to predict the BPA concentration quantitatively. Integration of the regression model with the developed sensor provides an accurate and portable smart sensor platform well‐suited for real‐time and on‐field monitoring of BPA.

Development of molecularly imprinted photonic crystal hydrogel based smart sensor for selective uric acid detection

Determination of uric acid (UA) concentration is important in clinical analysis, as its variation is an indication of several health-related conditions. Here, we discuss the development of a Molecularly imprinted photonic crystal hydrogel (MICPH)-based colourimetric sensor for the selective detection of UA. The developed MIPCH-UA sensor displays a bright structural colour, which varies as the sensor swells upon rebinding the UA molecules. The structural colour change is directly related to the concentration of the target molecule and can serve as an easy readout of the sensor response. This colour change can also be recorded spectrally, providing a quantitative measure of the sensor response. With a low limit of detection (LoD) of 1.01×10-9M, the sensor is capable of detecting low concentrations of UA. Moreover, the sensor endows the advantage of fast responsiveness and reusability when employed for UA assays. The sensor performance remains consistently reliable over an extended duration of up to one month, thereby ensuring cost-effectiveness in monitoring UA levels. The specific detection capability of the sensor allows the accurate and reliable measurement of UA in the presence of various interfering molecules and complex sample matrices. The structural colour change of the sensor was used to train a CNN-based deep learning algorithm to quantitatively predict the UA concentration. The integration of the machine learning algorithm with the developed sensor provides an accurate and efficient smart sensor platform well-suited for real-time sensing of uric acid.

Real-time and high-sensitive colorimetric sensor based on photonic crystal for amniotic fluid identification

In this study, we proposed a pH-responsive photonic crystal hydrogel sensor (PCHs) to conveniently and accurately recognize the amniotic fluid from urine of parturient women, which was constituted by three-dimensional polymethyl acrylamide (PMMA) array and optimized hydrogel. PMMA array was self-assembled by 180 nm monodispersed nanoparticles with vertical sedimentation method. The functional hydrogel containing N-acryloyl phenylalanine (APA), acrylamide (AM) and N, N'-methylene bis(acrylamide) (BIS) as co-monomer and crosslinking agent respectively, was photo-polymerized by the precursor under 365 nm UV light. This hydrogel significantly shrank or swelled corresponding to the acidity and alkalinity of the aqueous solution, which resulted in both the reflection peak position (λmax) of the prepared sensor and its structural color changing with the pH value. The λmax of PCHs redshifted from 514 nm to 606 nm in 60 s while the pH value of testing solution increased from 4.5 to 8.0, which exactly covered the pH value of amniotic fluid and urine. Correspondingly, its structure color gradually changed from pale-green to red ensuring their naked-eye determination. Furthermore, an extremely high sensitivity as 26.3 nm/pH of Δλmax was obtained which was linearly related to pH value. The prepared sensor possessed steady accuracy and extraordinary sensitivity compared with the pH test strip which was generally used in amniorrhexis diagnosis nowadays besides the advantages of the low cost, simple operation, rapid response and visual detection mode. The reliability of this PCHs was further confirmed by the real sample detection which relative standard deviation was below 5.0 %, suggesting its potential clinical applications.

Highly sensitive l-lysine molecularly imprinted two-dimensional photonic crystal hydrogel sensor

Using polystyrene two-dimensional photonic crystal as template, l-lysine molecularly imprinted two-dimensional photonic crystal hydrogel (l-Lys MIPCH) sensor with highly sensitive response to l-lysine was prepared by photoinitiated polymerization. The response performance of the l-Lys MIPCH sensor was investigated by observing the change of the diameter of the Debye ring (ΔD) and the structural color of the sensor. In the process of recognizing l-Lys molecules by l-Lys MIPCH sensor, the volume of hydrogel swells, the diameter of Debye ring decreases, and the particle spacing of photonic crystal increases. As the l-Lys concentration increased from 0 to 10−4 mol/L, the diameter of Debye ring decreased by 15.7 mm, the particle spacing of photonic crystals increased by 75.1 mm, and the structural color of hydrogel changed from blue to red correspondingly. When the l-Lys concentration was in the range of 10−12–10−4 mol/L, there was a linear relationship between the change in the diameter of the Debye ring (ΔD) and the logarithm value of the l-Lys concentration (lgc), and the linear relationship was as follows: ΔD = 19.04 + 0.90 lgc, R 2=0.9962. In addition, the detection limit of the sensor is as low as 10−16 mol/L. The prepared sensor not only has high selectivity, but also can be used for chiral recognition of l-Lys, and the results of l-Lys in the actual sample of lysiinositol vitamin B12 oral solution were also satisfactory.

Hepatocellular carcinoma biomarkers screening based on hydrogel photonic barcodes with tyramine deposition amplified ELISA

Hepatocellular carcinoma (HCC), as one of the most lethal cancers, significantly impacts human health. Attempts in this area tends to develop novel technologies with sensitive and multiplexed detection properties for early diagnosis. Here, we present novel hydrogel photonic crystal (PhC) barcodes with tyramine deposition amplified enzyme-linked immunosorbent assay (ELISA) for highly sensitive and multiplexed HCC biomarker screening. Because of the abundant amino groups of acrylic acid (AA) component, the constructed hydrogel PhC barcodes with inverse opal structure could facilitate the loading of antibody probes for subsequent detection of tumor markers. By integrating tyramine deposition amplified ELISA on the barcode, the detection signal of tumor markers has been enhanced. Based on these features, it is demonstrated that the hydrogel PhC barcodes with tyramine deposition amplified ELISA could realize highly sensitive and multiplexed detection of HCC-related biomarkers. It was found that this method is flexible, sensitive and accurate, suitable for multivariate analysis of low abundance tumor markers and future cancer diagnosis. These features make the newly developed PhC barcodes an innovation platform, which possesses tremendous potential for practical application of low abundance targets.

Wearable analytical platform for colorimetric detection of sweat lactate using spherical colloidal photonic crystal hydrogel

The construction of reliable and sensitive wearable sensors capable of monitoring specific targets in sweat remains a challenge highly relevant to a range of sensor/diagnostic applications. Herein, we develop a wearable microfluidic platform to monitor sweat lactate, in which spherical colloidal Photonic Crystal Hydrogel (PCH) is synthesized to construct the sensing part. Thanks to the structural color of PCH, lactate concentrations can be obtained via the eye-recognizable and low angle-dependent color variation. Accurate quantitative analysis is performed on a smart phone with Matlab code by integrating the linear relationship between hue value of sample photos and lactate concentrations. The developed sweat sensor presents good selectivity and long-term stability, and it is capable of detecting lactate accurately in human sweat within the physiological range. On-body measurement performed on volunteers successfully demonstrates the applicability of the developed device. This wearable analytical platform provides a promising tool for sweat lactate detection in sports science and medical diagnosis. And it is expected to contribute to developing user-friendly wearable biochemical sensor devices.

Opal photonic crystal double‐network hydrogel for visual detection through structural color and fluorescent responsiveness

AbstractPhotonic crystal hydrogels are widely used in the field of visual detection, based on the response of the structural color to external stimulus, such as pH, temperature, near‐infrared light, and so on. Here, we develop an opal photonic crystal hydrogel by combining polystyrene (PS) photonic crystals with a fluorescent double‐network hydrogel and focus on both its visual detection function and mechanical property. The opal hydrogel is composed of nanocomposite hydrogel as the first network and ionic crosslinked hydrogel as the second network. The introduction of PS photonic crystals and terbium ions endows the opal hydrogel distinctive structural colors and fluorescence, respectively. Because of volume changes, the structural color of the opal hydrogel selectively responses to metal ions and organic solvents. Attributing to the ion exchange interaction, the opal hydrogel exhibits fluorescent responses to various metal ions. Combining the responsiveness of structural color and fluorescence, a visual dual‐detection mode is set up, with better detection sensitivity and selectivity. Moreover, the characteristics of nanocomposite and double‐network crosslinking ensure the opal hydrogel enough mechanical properties to undergo cycle visual detection. Consequently, the fabricated opal hydrogel is promising for use in visual detection to multiple substances in single‐ or dual‐detection mode.

A Flexible and Free‐Standing Photonic Crystal‐Hydrogel Film for Enhanced Fluorescence from Nitrogen Doped Carbon Dots

AbstractEnhancement of fluorescence emission in a flexible and free‐standing fluorescing film is a key requirement for sensing platforms with augmented sensitivity. In this context, a study on the enhanced fluorescence emission from nitrogen‐doped carbon dots (NCDs) embedded on a flexible free‐standing photonic crystal hydrogel film prepared via photopolymerization, is presented. The composite structure utilizes the photonic crystal enhanced fluorescence (PCEF) technique and incorporates a self‐assembled 3D photonic crystal (3D PC) onto a photopolymerizable hydrogel matrix containing the NCDs. The 3D PC template is prepared through vertical deposition self‐assembly using monodisperse polystyrene (PS) spheres. By leveraging the enhanced excitation and extraction effect in a PC‐fluorophore composite, the authors’ structure exhibits a fourfold enhancement in fluorescence emission compared to the control sample. The relative positioning of the photonic stopband with the excitation and emission spectra of the fluorophore (NCDs) is thoroughly studied by selecting four different 3D PCs with varied lattice parameters. In addition, the hydrogel matrix offers improved photostability and enhanced lifetime for the NCDs. This structure can be further modified into an efficient sensor through appropriate functionalization.