Custom fabrication of glass microfluidic chips
Key properties of glass include: superior optical transparency (facilitating optical detection and observation), excellent corrosion resistance (resistant to chemicals, withstanding various acids, alkalis, and organic solvents, suitable for various chemical experiments and analyses), biocompatibility (suitable for applications such as bioanalysis and cell culture), and high-temperature resistance (suitable for high-temperature reactions and thermal cycling experiments), making it suitable for high-pressure or optical applications.
Glass possesses good thermal conductivity and stable electroosmotic properties; therefore, in practical applications, glass microfluidic chips are a commonly used medium in analytical and electrophoresis platforms. They can be used for the detection of proteins, nucleic acids, and intracellular biological components and markers.
Sample pretreatment processes can be completed within the channels of glass microfluidic chips through the construction of microstructures and microchannels within the chip, such as solid-phase microextraction, separation, and mixing.
The superior optical transparency (enabling real-time process analysis) and excellent high-pressure resistance (high mechanical strength) of glass microfluidic chips make them the optimal choice for many applications. Glass is highly favored in the industry due to its well-defined surface physicochemical properties, biocompatibility, chemical inertness, hydrophilicity, good light transmittance and electroosmosis, electrical insulation (enabling its use in applications requiring electric current), high mechanical strength, easily modifiable channel surfaces, low fluorescence background, and ability to allow for efficient coatings.
* Glass is a material with high transparency in the visible light region, making it ideal for microscopy and other optical analysis procedures. Furthermore, there are glasses with low autofluorescence to ensure extremely low background noise in fluorescence techniques.
* Chemically, glass is highly inert. It does not swell upon contact with organic solvents and effectively prevents reagent diffusion. Its surface is hydrophilic, thus easily wetting with aqueous solutions. Surface properties can be easily tuned through various techniques, such as plasma treatment or grafting, and even the incorporation of functional chemical groups, enabling the binding of various biomolecules, including DNA and proteins.
glass material：B270、BF33、D263......
Wet Etching
High processing efficiency for microfluidic glass chips with channel depths exceeding 20µm and aspect ratios exceeding 2:1.
Sodium-calcium/soda ash glass wet etching: etching depth 5-500µm, tolerance 2%; condition: width greater than twice the depth.
High borosilicate glass wet etching: etching depth 5-150µm, tolerance 2%; condition: width greater than twice the depth.
The basic process of glass microfluidic chip fabrication technology includes steps such as resist coating, exposure, development, etching, and resist removal. Depending on the channel conditions, wet etching or dry etching can be selected. Wet etching is isotropic, while dry etching is anisotropic. Currently, wet etching is the most commonly used method for microfluidic glass chips.
Glass Microchannel Machining (Soda-lime Glass, Borosilicate Glass, Quartz, etc.):
* Maximum Machining Size: 400*350mm;
* Minimum Channel Width: 600 micrometers, Aspect Ratio ≤ 3:1;
* Machining Accuracy: ±0.03mm;
* Minimum Drilling Diameter: 0.7 mm, Drilling Accuracy ±0.03mm;
* Surface Roughness: Ra3.2;
Glass Microchannel Laser Machining:
Minimum Machinable Linewidth: 50um;
* Aspect Ratio Required: Less than 1:1;
* Maximum Machining Depth: 1mm.
Glass Microfluidic Chip Design Services
We can provide glass chip design services according to customer needs, meeting requirements related to temperature resistance, pressure resistance, corrosion resistance, heat exchange, sealing, size, and experimental requirements!
Large-format glass designs require consideration of venting channels to ensure adequate degassing and prevent air bubble formation during sealing.
When designing and customizing glass microchannels, it's crucial to consider the area not reserved for other materials to avoid waste. Larger areas are more prone to air bubbles during sealing. A symmetrical design on both sides significantly reduces risk and improves aesthetics.
If using quartz glass for microchannels, bulk quartz must be considered. Laser treatment of non-bulk quartz can affect the channel, causing edge chipping or ablation.
Cleaning Methods for Glass Microfluidic Chips: For rigid chips like glass chips, if the chip channel surface is uncoated, a 1 mol/L NaOH solution can be used. If the chip channel surface is coated, high-concentration alkaline or acidic solutions should not be used, as prolonged cleaning will corrode the coating. In this case, a low-concentration acid or alkaline solution can be used to quickly rinse the chip channel, followed by rinsing with deionized water to remove any remaining acid or alkaline solution. Finally, use a gas (air/oxygen/nitrogen/argon, etc.) to dry the liquid inside the chip channel.
Typically, the order in which different liquids are used for rinsing will leave slight residue on the surface of the chip channels. This is because different liquids may react chemically or have different densities and viscosities, and cross-rinsing can leave some liquid residue. If you are concerned about these residues, you can first rinse the chip channels with the reagents used in the experiment, then rinse with deionized water, and finally rinse with ethanol or isopropanol (IPA) solution. If IPA solution is available, it is best to use IPA to rinse the chip channels last, as IPA is highly volatile and will not leave liquid traces on the surface of the chip channels.