MasSpec Pen

Key takeaways

MasSpec Pen belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect MasSpec Pen to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MasSpec Pen from memory before moving on to harder problems.

Reference excerpt

The MasSpec Pen is a mass spectrometry (MS) based cancer detection and diagnosis system that can be used for ex vivo and in vivo tissue sample analysis. The system collects biological molecules from a tissue sample surface via a solid-liquid extraction mechanism and transports the molecules to a mass spectrometer for analysis. The composition of the extracted molecules can then be used to predict if the tissue sample analyzed contains cancerous cells using machine learning algorithms and statistical models. In early-stage clinical research, the MasSpec Pen system was able to distinguish various cancer tissues, including thyroid, breast, lung, and ovarian tumor tissues, from their normal counterparts with an overall accuracy of 96.3%. A follow-up study in illustrating the use of the device for detection of serous ovarian carcinoma in ex vivo tissue biopsies allowed for the discrimination of normal and cancerous ovarian samples with a clinical sensitivity and specificity of 94.0% and 94.4%, respectively.

Development and current usage Livia S. Eberlin, Ph.D., an Assistant Professor of Chemistry at the University of Texas at Austin, first reported the invention of the MasSpec Pen in 2017. Within her laboratory, the device has been used to analyze human tissue biopsies, including normal and cancerous breast, lung, ovarian, and thyroid samples. The MasSpec Pen is currently being evaluated for use on freshly excised tissue biopsies and for intraoperative use during oncology surgeries. The MasSpec Pen has been licensed to Genio Technologies, Inc., a subsidiary of MS Pen Technologies, Inc.

Principle of operation

Ambient ionization mass spectrometry for disease diagnosis The MasSpec Pen technology is based on the principles of ambient ionization, in which ions are generated directly from a sample without need for extensive sample preparation or chromatographic separations. The MasSpec Pen can further be categorized as a solid-liquid extraction based ambient ionization method, described as methods that utilize a solvent system to gently extract molecules from a sample surface that are subsequently analyzed by a mass spectrometer. Desorption electrospray ionization (DESI) was the first liquid-based ambient ionization MS method. DESI employed a spray of charged solvent droplets to bombard a sample surface to desorb and ionize molecules from the sample surface, which are then directed towards and analyzed by a mass spectrometer. DESI-MS and other solvent-based ambient ionization MS methods has been widely employed for the analysis of small molecules, primarily metabolites and lipids, directly from biological tissue specimens to determine their molecular composition and leverage the mass spectral data acquired for diagnostic purposes. These methods have been deployed for the discrimination of normal and cancerous regions of tissue samples for many solid tumor indications, including breast, brain, prostate, ovarian, and colorectal, among others. Multivariate statistical analysis methods are often utilized to generate statistical models from the mass spectral data acquired from direct analysis of tissue samples to distinguish between healthy and diseased tissues.

MasSpec Pen analysis mechanism The MasSpec Pen, initially described in 2017, is a solvent-based ambient ionization technique but differs from its predecessors due to the handheld nature of the device, allowing analysis of samples distant from the mass spectrometer in a geometry independent manner. The MasSpec Pen used a probe that can be manipulated by hand to direct the analysis. To use the system, the tip of the 'pen' is placed in contact with the surface to be sampled and the user triggers the initiation of a sampling procedure by pressing an integrated foot pedal. This signals a syringe pump to deliver a small aliquot of solvent through a polymer tube to a reservoir at the tip of the 'pen' that remains in contact with the sample. Analytes are then extracted from the sample into the solvent droplet by a solid-liquid extraction mechanism. After a 3 second extraction period, the droplet is aspirated into the mass spectrometer using the vacuum from the mass spectrometer as the vacuum source. Once inside the mass spectrometer, the analytes within the solvent droplet are de-solvated and ionized via an inlet ionization mechanism. The ionized molecules are then analyzed by the mass spectrometer analyzer and the mass spectrum resulting is generated.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with MasSpec Pen

Start with the simplest possible case. Write down what MasSpec Pen claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to MasSpec Pen before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about MasSpec Pen ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of MasSpec Pen

In research: MasSpec Pen appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses MasSpec Pen in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: MasSpec Pen is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cancer screening, so understanding it makes those chapters shorter.
In everyday life: Look for MasSpec Pen outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study MasSpec Pen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MasSpec Pen means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain MasSpec Pen out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MasSpec Pen in simple terms?

The MasSpec Pen is a mass spectrometry (MS) based cancer detection and diagnosis system that can be used for ex vivo and in vivo tissue sample analysis. The system collects biological molecules from a tissue sample surface via a solid-liquid extraction mechanism and transports the molecules to a ma…

Why does MasSpec Pen matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study MasSpec Pen?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on MasSpec Pen.